If it's just a bad motor, you can get a Jspec clip for the AW11 (MK1 mr2) from either motors unlimited (I forgot their number) or you can check out the inventory at
http://www.neishlinmotors.com/
You'd be looking for a 4AGE or 4AGZE, the latter being the supercharged motor. Plus, if you plan to change the motor yourself, get the toyota service manuals. Try to weigh the costs of buying the car and buying a new motor to buying a working car. Either way, if you go with the MK1, you won't be disappointed.