First of all you shouldn't have let your girl drive your Supra, as it happens to be the only thing more jealous than a girlfriend and probably broke to teach you a lesson.
If your accelerating hard and its worse than when you accelerate soft then it could be a fuel supply or ignition issue. The engine demands more but the pump, filter, regulator, or injectors just arn't making it happen, or you somehow dented a fuel line which is very very difficult to do just driving. It sounds like, besides the possibility of a huge ECU or CDI error, that your ignition was more or less made about as good as it is going to get. If you would describe the motion of the car when it is expierencing this problem has "Herky Jerky" there is a good chance its fuel related.
A filter is cheap and so is a bottle or injector cleaner that you can just poor in the gas tank. Also, use some Seafoam on that bad boy. FOLLOW THE DIRECTIONS AND READ THEM ALL BEFORE YOU USE IT, heheh. My Supra loved it some Seafoam. Try the above real quick, especially if you havn't replaced the filter before. Good luck, come back and let us know how it went or if you need more help.