You lack vital information in your advertisement such as the trim, and mileage. It sounds like, unless you find a sucker, you are going to be lucky to walk away with $500, not $5000. After market parts add little to no value to a car, unless it is serious performance parts (built engine, forced induction). They certainly do not make your car double in value. As it sits now, my guess is it is not running because the timing belt broke, not just that it is getting time to replace it. You probably have more damage to the head than the car is worth. The car is just going to sit and rot unless you get realistic with your asking price.