Troubled actor Robert Downey, Jr. says he's been drug-free, flat broke, and looking to make amends with his family since his release last month from a California Substance Abuse Treatment Facility and State Prison.

"I so appreciate the simple things now," the 35-year-old Oscar nominee tells Details in his first post-prison interview. "When I got out, I stayed in this middle-class house with a boat and a muscle car. I had a little room. It was the kind of place where I used to say, 'Okay, I can rough it here for two days.' Now it was like, 'Wow! I've got my own bathroom! The toilet has a lid and it isn't made of metal!"

Previously accustomed to tooling around L.A. in high-priced sports cars, Downey now finds himself making $300-a-month payments on his Chevy Monte Carlo SS. "I'd never bought an American car before," he says. "This might sound a bit pathetic, but I like America a lot more than I ever did before."

Downey, who's looking to pay off his financial debts through an upcoming stint on Ally McBeal and other acting jobs, says most of the money he made in Hollywood over the years went to support his insatiable drug habit. "The running joke, particularly when I was with [former live-in girlfriend Sarah Jessica Parker], she would say, 'You just made more money in your last six weeks than I've made in my whole career, and yet I have money and you're broke and asking me for five grand. What are you doing?' I'd say, 'I don't know. I'll check the trunk. I'm sure there's a bag of something or other that will explain it.'"

Clearly, one of Downey's greatest regrets about his years of substance abuse is the toll it has taken on his family. He longs for reconciliation with wife Deborah Falconer [they're legally separated] but she is now living with another man and he believes the marriage is probably doomed.

"I was an a-hole, a total a-hole," he admits. "And basically, this is all my fault."