Any good furniture re-upholstery shop should be able to fix the seat for you. You just have to unbolt it and give it to them.
Depending on what car you drive, you might also want to consider going to the auto wreckers and buy a seat from one of their wrecks. Might take you a while to find a replacement seat, but it'll probably be quite cheap.
Of course, if you ask me, the best option is to get a proper sports seat as Philip was suggesting la~ 
-Lik |