Most likely your transmission is in limp in. It is in 2nd or 3rd gear (can't remember which). You can drive it to a transmission shop but drive it as little as possible.
If you are mechanically inclined it's not too hard. You have to take out the battery, tray and the bracket that holds the battery tray. Disconnect the trans cooler lines, remove the input speed sensor and remove the harness fromt the solenoid pack. Three bolts hold it on the trans. Make sure the mating surface is VERY clean before you put the new one in.
