I think that he should upgrade tonight. I bet that he could be to his friend's house in, hmmm, 50 minutes.
Kidding aside, that computer sub is actually pretty impressive - but mostly only when it's fed a Dolby Digital bitstream. For analog audio feeds, it's not the best, though, and certainly not up to par with a "real" sub like the B&W, SVS, or the like. However, it's probably more of a sub than most people think of for computer speakers.
I have an impression that one of the things that holds that sub back, as well as any other one, is locating it in the cabinet behind the TV.
Jon - have you tried your current sub in the rear corner of the room?