How can you find out your car's value if it is being totalled by the insurance company?

My 98 Mustang, was hit & totalled. The driver took off. I have full coverage ins. so it will be covered. I am out of a car & have no idea what value it has. I looked on KBB, but which value do they give you? Trade-in, MSRP? Is there anyway for me to prove my car is worth more? I am worried I will only get $1,000 for a car they can easily sell for $6,000. Anyone have any suggestions?