Good luck. While parts may only be 5K, the labor will be probably another 2K or more. What happened, did the moron back into you?
As long as the airbags didn't deploy, it all looks fixable.
To determine diminished value, look at
www.kbb.com, edmonds website, any place that you can look at to determine fair retail market value. Get several, add them together and divide by the number of places, that will get you a ball park figure. Then do the same thing again, but when they ask if there has been an accident, check 'yes'. The difference will be your diminished value.
A word of caution, if the insurance company accepts the claim for diminished value, that is usually added to the cost of repair. That could put the vehicle into the 'total' category as being too expensive to repair. If you are competent or know of someone who is competent with repairs of this type, if they are going to total it, buy it back and fix it yourself. It depends on if you are still making payments on a loan, that should be factored in the decision to buy back and fix it yourself. Personally, if they offer to total it and the car is paid for, take the money and get another Z.