does your house have any steel structure? Is it an older house with poorly shielded wiring? what brand of receiver are you using, on what computer?
there's many different things that can have an effect on wireless performance. I was using one of the MS (yeah, yeah, boo, hiss. it was free) USB adaptors and an Apple Airport card on my iBook 600, and I was able to go all the way outside, to the other end of the apartment building. they both also receive a dude's wireless connection from a neighboring building, who's using a linksys router (I know because the network's name is "linksys")
it can be really funky at times