How do I get my neighbors to pay for the headlight the busted put of my 1988 Saab

You have a few options. I would submit the claim to your insurance carrier to confirm what your mechanic has told you. It may be he is wrong and they will fix the damage. If they do, they will go after your neighbor for what they paid out. If they determine you car is totalled they will have to pay you the market value of the car. You can still keep the car but your insurance company will deduct the salvage value from the market value. If the damage is at least $1000 you can file a Motor Vehicle Collision Claim for Damages with the Department of Motor Vehicles. If they determine your claim is valid they will suspend your neighbor's license until the damage is paid for. You can do that here:http://www.dol.wa.gov/driverslicense/collision.html  If the damage is under $1000 you can file a claim for damages in Small Claims Court. You might want to advise your neighbor you will be forced to pursue legal action if he/she does not take care of the problem.