You can run a bluebook value on edmunds, but I think that's about right. Bluebook doesn't deal with much except general condition, age, and original cost.
If you can't come to terms with the insurance company, I'd suggest contacting the owner of the other car and the driver's parents and seeing if they'll agree to make up the difference out of pocket (but get that in writing if you do, and make sure you get down all the particulars about the accident in that document.) If you're willing to be nice about filing charges, they should be nice about the money (a lawdog would cost more).
If you can't come to terms with the insurance company, I'd suggest contacting the owner of the other car and the driver's parents and seeing if they'll agree to make up the difference out of pocket (but get that in writing if you do, and make sure you get down all the particulars about the accident in that document.) If you're willing to be nice about filing charges, they should be nice about the money (a lawdog would cost more).