sort of an in car problem

A Bose sound dock is not cheap, certainly it costs more than a lower end head unit with free installation at Best Buy.

The car may not be worth fixing to you, but it would probably be cheaper to fix the car's control unit (if in fact that is the problem, replacing all the speakers would be an expensive endeavor).

Speakers are the cheapest thing in the car audio lineup. Head units often cost > $200 dollars, amps can be several hundred bucks as well. You can get a killer set of component speakers for under $150. You can also get a real good pair for about $50 or so. Replacing your stock paper cone speakers will also make the most noticable difference on your system's sound. Alos going the soundock route you now have things lying in your car that will most likely fly about. How do you plan to secure these items? There is a bunch of stuff for car audio that fits every budget. I suggest something that was actually meant to work in a car. Order from crutchfield as they give you detailed instructions on how to install things yourself. If youy can use a screwdriver you can pretty much replace your stock speakers. It's not hard at all. DON'T pay some 14 yo kid at BestBuy $50 to put in your speakers. You can do a better job in your driveway for $0.