Moody Wireless Network

My Wirless Network seems to have its own Moods. My wireless router is in the basement,and my computer equiped with a netgear wg11 802.llg is two floors up. Usually I have a good signal at a 11mbps,sometimes 5.5mbps.wich is not a problem. The Problem is that sometimes it shows I have a Signal at 11mps but when I go to internet explorer it says page not found.This happened to me about last week,when I was on it in the morning for a long time downloading big files and then in the afternoon it just stoped working yet it showed the signal at 11mbs.So restarted the computer and did a spybot scan and tried everything until late at night but nothing happened ,and then the next morning I go on and Bingo its as fast as flash.And today the samething happened (currently on aol 56kdialup,and its killing me,guessed i got spoiled)Does anybody know what Im talking about?anything?                                 Also on a seperate issue when somebody goes on the cordless phone on the floor my computer is on I loose a signal does that make sence?does it happen to you,please help me,hopefully tommorow morning it will work.