Hauser,
In almost all cases, personal auto policies are written as ACTUAL CASH VALUE. That means, you are SOL, unless you have new car replacement coverage from your insurer (car needs to be less than 2 or 3 years old), or some sort of Gap coverage. Because you were not at fault, you are at the mercy of the teenagers's policy to pay, but if you have the replacement coverage on your own policy, you may have some recourse.
I'm sorry for your loss.
Mike