The 45 year old, who also played Madonna's teammate in baseball film A League of Their Own, was arrested in Venice, California in May (09) after allegedly hitting a teenage skateboarder with her car.
She was initially charged with DUI with injury, DUI with a blood alcohol level of .08 or higher with injuries, and driving without insurance, but the counts were dismissed as part of a plea deal, and the DUI charge reduced to a misdemeanour.
Petty's lawyer Blair Berk appeared in Los Angeles Superior Court last week (ends28Aug09) for the sentencing hearing.
The actress, who was not present, was also ordered to pay fines, undergo outpatient treatment for alcohol abuse and attend Alcoholics Anonymous meetings.
The teenager she reportedly knocked down only suffered minor injuries, reports People.com.