You talk to your insurance company. If the car is a write off ( if damages = 80% or mroe of car's worth, then it will be a write off ) then and only then will you have to think about the $ part. If it is as bad as you say, and it is a write off, then you usually get replacement value, or what a car with the same milage and same condition could be bought for. Aftermarket items are usually not covered. (such as brush guards and the like )
If your car is fixed and the percieved value has gone down, then it may be time to contact a lawer. But frankly, I doubt anyone would take the case as no judge would concider the value of a wrecked and rebuilt car different from a unwrecked car. they see it as good as new unfortunately.
If you and yoru family is hurt, then it is time to get a lawer. The insurance and the driver ( and his family since the other driver is under contract age ) needs to cover any and all medical bills and lost wages. NO question. get you and the others in the car throughly checked out both by a doctor and a chyropractor ( or someone to make sure you have no tissure damage that may rear it's ugly head later )
IMHO, Lawers suck. only use one if it is absolutely neccessary.
Glad to hear that no one was seriously hurt. In the end, that is all that really matters.