kdc-122 is pretty low-end of the line for Kenwood. (No offense there) Anything in the middle section of a line should have decent laser pickup on it.

Stay away from Aiwa, Panasonic and Sony and stick with Kenwood, Eclipse or Alpine.

If you dont have the money, then why not just get a splitter off the back of the radio for the RCA's? There's no reason to have left and right fader on a pair of subs anyways.

Oh, and I bet you if you open the radio, the contact going to one of the RCA' plugs is broken, which can be caused from pushing in or pulling out the RCA's with too much force. You can always try soldering back if you can find the break...