My 2001 Ford Tuarus SES shifts gears irregularly and the key doesn't easily turn on the car, I have to jiggle it a little, it putts until it warms up, my battery just died, so I bought a new one.

It sounds like you have multiple things going on with this car. Gears shifting irregularly could be a bad Vehicle Speed Sensor (VSS), failure of the Manual Lever Position (MLP) sensor. Then again it might be a torque converter or simply low fluid in the trans. I'll assume since you had it to a shop those would have been checked and that they recognized it was a bad sensor/computer. You can reset the computer by disconnecting the battery for 30 mins (although you might want to scan those trouble codes first) and see if it affects performance. If you can get it up to an auto parts store (Autozone, Advance, O'Rielly) they will scan for trouble codes and can also check the alternator and battery for free. When working on any computer or sensors on a car disconnect the battery. A new ECU/ECM computer is around $250 to 300 for the part. It's not difficult to change, it's located under the cowl. I do believe however it has to be programmed as they are parts specific and encoded to their vehicle. That can be done by a tech with a Tech 2 Scanner, or by a qualified shop or the dealer.

Thanks for the advice KenF, thanks again.