I borrowed a car from a friend a few summers ago. She had accidentally clipped soemthing and it took off her driver's side mirror. THe repair shop made a "temporary fix by using a couple of long screws to put it back on. The electronics still worked so it could be adjusted and you really couldn't tell that it was knocked off so she just left it. Why bother when the screws were holding tight and the thing worked fine. Might be worth looking into unless the damage is worse on your car.