You should let the dealership do it for free. There is a recall on it. Here is the info:
Recall 96V017000: Ignition Switch Defective
Defective ignition switches were improperly manufactured and can cause some electrical accessories to malfunction. Some electrical accessories, such as, turn signals, windshield wipers, lamps, power windows and air conditioners can malfunction when the car is started.
Dealers will replace the ignition switch.
SYSTEM: ELECTRICAL; IGNITION; SWITCH.
VEHICLE DESCRIPTION: PASSENGER VEHICLES.
NOTE: OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME, SHOULD CONTACT AUDI AT 1-800-822-2834. ALSO CONTACT THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION'S AUTO SAFETY HOTLINE AT 1-800-424-9393.