2006 Chevy Cobalt Key stuck

I tried to start my car last night and found out the battery was dead. (my car hadn't been driven in about a month) When I got out of the car, the key was stuck in the ignition. I was able to turn the steering wheel, but still the key would not come out--it will not turn all the way back to the start postion. I'm able to turn the key to start the car, but can't turn the key back.