Either way, the data still has to get to the PC's, right? You planning on having the Access point directly wired to the PC? Sounds much more simple to get the wireless cards and call it good.
An AP or a bridge is just a Wireless Jumper-wire IMO. You already have an Access point in that wireless router. So adding another AP is kinda moot unless the signal doesn't reach that far, then you can get the AP or Wireless bridge. (That thing should travel through a wooden home very well. Some apartments/duplex's may have trouble with lead paint or something. I know this place has issues:p)
Me, I have a WMP54G card and I'm not even wireless anymore:p I'm bass ackwards:p
This is a pretty good FAQ IMO: