Beautifully stated Brucelee.
When you talk to the insurance company about the value decreasing due to the repairs, use the term "diminished value" so it sounds like you know a lot about dealing with insurance. In Georgia, they are required to pay for diminished value. Like Brucelee said, get a dealer to check it out and give you the number since they know more about the car's value than most.
Check with your state's insurance commissioner's office to see if diminished valued is required before you talk to the insurance company. Then be as nice as possible with your dealer's estimate and see if they say ok or give you a hard time. If they give you a hard time and they're required to pay it, let them know you've checked and know they must pay it while still being nice. You should not have any trouble after that, but if you do, let them know you will file a complaint with the insurance commissioner's office while still being nice. It usually will not go that far.