For bad wireless reception, that'd be in the networking forum, but here's some short answers:
Download iStumbler or MacStumbler--that's the only way you're going to get real answers. For example, someone might have setup another WAP nearby on the exact same channel as yours. Or someone nearby just got some new cordless phones.
After getting some reception numbers from iStumbler, then you should change the wireless channel on the WAP and see what reception the new channel gives you.