If it's insurance related, they should pay for a rental while the car is in for repairs. If not and it's just the bumper, have the shop cut out a piece of the existing bumper for paint match and shoot the new bumper before you bring the car in. Then it will only be about an hour or so to swap the part out and you can wait for it.
Also, that shop that Crazy Bimmer mentioned does pretty good work.
