Guy hit my truck. His insurance wants to total my truck, but won't pay enough to replace it. Can I make them fix the truck, and pay for a lawyer?

My Grandson was driving my truck and was hit by another driver, who initially admitted responsibility, now denies it. He got a ticket for the accident. His Insurance says they will give me 7700 and some change for my pickup, but won't fix it because it will cost over 8000. Pretty sure that's presuming the rear-end and transmission are alright. I told them I would take 15,000 for the truck, they could fix my old truck, or they could replace it with something as good or better. They choose to do none of the above. Can I sue them to make them fix the truck, while supplying me with a rental, and also pay for my lawyer?