Use SEM Color Coat, which comes in aerosol cans. You need to clean it with SEM Soap, then use World Class Vinyl/Plastic Prep until water doesn't bead up on it, spray it with Sand Free, let it flash for about 15-20 minutes, and then apply the Color Coat. It will turn out perfect.
BTW, you can get away with washing the fabric seat covers in the washing machine, but use the gentle cycle and let them air dry, don't put them in the dryer.
No one lives forever, the trick is creating something that will.