You'd get more suggestions in the networking forum.
Download iStumbler or MacStumbler, and use them to figure out which channel works better on your WAP as well as what location in the house gets better reception. Walking a few feet one direction or another can dramatically change reception (conduit in the walls, lots of stuff like that.) Also, depending on whether you've got 2.4 ghz cordless phones, etc.
Changing the location of your WAP is also measurable. Different brands of WAPS vary dramatically in wireless reception--my new Hawking next to my Buffalo Airstation gets better reception.