First and foremost, focus on getting the car repaired properly. Nothing else matters more than this. Remember, the quality of the work will dictate the value lost, not to mention the appearance/performance of a car that you will most likely be driving for a few years.
After the repairs are complete, you can contact a few local dealers to see if they can assist you. Most will be happy to. They can give you a good idea of what the car would be worth with the repairs completed, and what it most likely would have been worth without. Your insurance company will most likely want a few estimates.
Make sure that before you sign off on any release from the insurance company, that you have talked to them about the diminished value. They should also be willing to guide you.
Again, best of luck.