Side mirror repair; warranty question

Just purchased used XV70, 2007 model, 20k miles, last week. Beautiful
car, looks and drives as good as new.

The next day my wife crunched the driver side mirror. Looks like a
total loss. So, this is my first repair.

Should I have it done at a Volvo dealer, or an independent repair
shop? What can I expect this to cost?

Also, is there anything I should do to register this car with Volvo to
lock in the warranty? Should I be aware of anything I could do to
void the warranty?

Thanks, from Boston.