I agree with John. Find an independent. I charge $900.00 for that job, and that's with labor, the evaporator, the drier, o-rings, freon and tax. Admittedly, I may be a little less expensive than most, but I just feel so bad for somebody when they need the evaporator. What is your car's delivery date? Are you just barely out of warranty? Had you been to the dealer multiple times and had the AC recharged while under warranty? If you did, you can prove that the problem existed while under warranty, and "sometimes" get it covered on "good faith".

Chris