If the HU is cd changer capable, you might be able to buy an adapter to turn it into an aux in by a fair amount of circutry (my boss got one for his toyota, not the tiny box i was expecting). If you search you should be able to come up with it.
and as far as the sb live goes, it really isnt a bad card as far a gaming audio goes. its one of the better consumer cards out there. the major complaint has always been the complete lack of competent driver support for their cards, and being the soundcard company, recycling products with a new feature or two (audigy = +firewire basically).
edit: hey look, found it: