Charlie Sheen's ex, Brooke Mueller, threw a birthday party for twin sons Bob and Max, on Saturday, while the boys' dad Charlie Sheen was nowhere in sight ...

That didn't stop the newly-rehabbed Brooke or her boys from enjoying a sunny afternoon in the park. The kids' school friends attended and everyone appeared to be having a blast. Mueller was the ultimate hands-on mom, carrying the boys around to all the play structures and taking them in the bounce house. Our photographer on the scene tells us: "Brooke looked so happy and the boys were in heaven. They seemed so glad to be with their mom and just running around being regular kids. And when the birthday cake came, they went wild!"

Happy birthday, boys!

After checking out of a 3-month rehab program in February, Brook Mueller has been working hard on her recovery via an outpatient program, and it definitely shows! The 34-year-old looked happy and healthy as she ventured out in Westwood to pick up frozen yogurt for her twins, Max and Bob, on Tuesday afternoon.

The former Mrs. Charlie Sheen showed off a much healthier frame in a black T-shirt -- which read "Hell is so hot right now" -- paired with a leather jacket and jeans, and still rocking her newly cropped 'do.

Mueller has been focused on spending all of her time with the twins since returning home, and she's gearing up to celebrate their third birthday with daddy Sheen, on March 14.

Keep up the good work, Brooke!

Brooke Mueller was spotted taking her twins Bob and Max for ice cream in LA yesterday, and Charlie Sheen's ex was looking happy and healthy when we snapped her photo. And how adoooorable are her little boys?!

Brooke was arrested in Aspen last December for felony possession of cocaine and for suspicion of assault, and she recently finished three months of intense drug treatment at Cirque Lodge in Utah. It's definitely paid off -- the mother of two is looking better than ever!

Brooke Mueller has definitely maintained a healthy lifestyle since leaving rehab at Cirque Lodge.

Charlie Sheen's ex went for an afternoon run with a sexy friend in the Hollywood Hills. Great to see Brooke workin' on her fitness.

The 34-year-old mother of two had been undergoing intense drug treatment at the Utah facility following her arrest in Colorado for drug possession and assault.

One step at a time, Brooke!

Brooke Mueller enjoyed a coffee break with a friend in West Hollywood while her lawyers and the prosecutor focused on getting Charlie Sheen's ex a plea bargain in connection with her arrest at an Aspen nightclub on December 3.

Mueller was arrested that night with felony possession of cocaine and on suspicion of assaulting another woman at the bar. As a result, she spent three months in rehab at Cirque Lodge in Utah.

Online reports claim Brooke's lawyer, Yale Galanter and the Pitkin County, Colorado prosecutor are gunning for a deferred prosecution which would include community service and drug ed classes instead of jail time.

Brooke's next court appearance was scheduled for March 5, however it has now been moved to April 2.

After making major progress in treatment at the Cirque Lodge in Utah, Brooke Mueller has officially left rehabilitation, and will now begin the transition to an "aggressive" out-patient program in LA.

A rep for Mueller said in a statement:

"After successfully completing an intensive three-month drug and alcohol treatment program, Brooke returned to Los Angeles yesterday and has immediately begun an aggressive outpatient program that includes a sober companion. Brooke is feeling better than ever before, and is committed to continuing treatment for as long as necessary to maintain her total and complete sobriety."

This is the longest Mueller has ever stayed in an in-patient facility, after she checked in on December, 12, following an arrest for drug possession and assault in Aspen, Colorado.

The 34-year-old reality star is planning to continue an out-patient program for another 30-45 days in LA, which will help her transition back to a normal, drug-free life.

Mueller has also been receiving support from ex-hubby, Charlie Sheen, whose been helping take care of their two-and-a-half-year-old twins, Bob and Max, while mom's been away.

Welcome home Brooke!

Rehab does a body good!

Looking healthy, fit, and rocking a short new 'do, Brooke Mueller made her way to Gold's Gym outside of the Cirque Lodge facility in Orem, Utah, where she is currently receiving treatment. X17online broke the news of Mueller's treatment when Demi Moore was believed to be attending Cirque alongside Brooke. Turns out Demi is NOT at Cirque Lodge, but the treatment center is doing wonders for the mother of Charlie Sheen's twins!

Sheen's ex-wife is very serious about her recovery and has been making great strides at the rehabilitation center, after she was arrested for assault and cocaine possession with intent to sell, in Aspen, Colorado, last December.

This is the longest Mueller has ever remained in a treatment program, and after two months she's said to be doing so well, she even stopped smoking cigarettes!

It appears Brooke is well on her way to a happy and healthy 2012!

Brooke Mueller is in rehab at Cirque Lodge in Utah, X17online can exclusively report.

Charlie Sheen's ex, who was arrested for cocaine possession last December in Aspen, Colorado, has been at the facility, located in Sundance, for several weeks.

Various reports claim Demi Moore is at Cirque Lodge, as well, and while those claims, we stumbled upon the news that Sheen's ex is there.

A source tells X17online exclusively:

"Brooke is in treatment and doing fine. She doesn't seem too stressed or worried about it. You can tell she's been through this before. Honestly, she'll get through it and she knows there's a good chance this won't be her last time in rehab."

Our source adds that Brooke's parents are staying at a cabin near Cirque Lodge with twin sons, Bob and Max ... bringing them to visit their mom regularly. Mueller is expected to stay at the facility through the month.