Actually, your car is still under transmission warranty. Your particular model has a 100,000 mile extended factory warranty on the transmission.
BTW, they've fixed the transmission problems now...they figured it out and since last fall have been producing trouble free transmissions. The transmission you got was likely manufactured before that, your dealer is an idiot.
Only 1.6% of transmissions were defective...hardly an epidemic. Pretty odd how you actually lost control on the highway from the 4-2 downshift...the NHTSA just closed an investigation on it because so few people even had the problem to begin with, and on top of that a very minute amount of people were injured because the car was still very driveable. Not at all like the steering column locking up on Corvettes.