That's a strange result, IMO. It could be due to the construction of the house as well. The wireless NIC that is attatched to the PC I'm using at the moment is the distance you're at, a floor above the router, through two walls and a set of stairs. The config utility says I have a 73% signal strength, and I'm at 11 Mbps.

This is with two Linksys products, though. That may not add a whole lot to it, but I also have no problems in another setup at my house, in which the router is in a closet in the middle of the house, and 30 feet away through several walls and the closet door, I get a signal with no problems with Linksys bridge.