Why does my wireless connection suck and vanish?

I have a cisco E2000 and when im playing black ops my connection is terribly low even though it is technically right beside me and no one else is logged on to it. Sometimes its the third bar of green but most of the time its dwindling between yellow and red and i'm lagging like crazy. The other problem is that t's signal vanishes. I have it wired to my computer but use it wirelessly for the ps3 and sometimes usually after a shut down the signal of my connection it never shows up and the little globe on my vista never shows and there's an x or just two lit up computers, even though sometimes i can still contact the setup. How could something privately used and so close to me screw up as if i was using the connection from a mcdonalds 10 blocks away with a bunch of retarded laptop people on that same connection at once?