Radiator steaming, car won't go past 10-15 mph

I just bought my 08' Aveo 2 weeks ago. Last Thursday I start up and leave to get my spare key from the dealer. The check engine light comes on and the car doesn't go past 15 mph, even if i put the pedal to the floor. I park, pop the hood, and see steam coming from the radiator. I cant find any leak, and the coolant reservoir is full to the top and steaming as well. I try to start up again, but this time it takes three tries before it starts up, and there is puttering like it does not want to start. While in idle, the car is revving itself without me touching the gas pedal. I have no warranty and no clue of the problem. Can anyone help me figure out what it wrong?

It sounds like a blown head gasket, or other major engine issue. But that's just a guess and the first step in the diagnosis is to read the OBD codes. You should try taking it back to the dealer and see if they will make it right for you, regardless of no warranty.

Thanks for your reply avguy. I took it to the dealer and they are supposed to contact me tomorrow. I really hope they will make it right because I really don't need these type of problems on a car a just started payments on.