If you want to do gaming, you wouldn't want your flaky WiFi to carry the signal in that crowded area. I haven't tried gaming on WiFi, but maybe others can share their tales of woe. :)

I don't know if a modem could improve quality and drown out the background clutter, but those windsurfers should improve directional quality. I'm going to make some windsurfers for myself, been putting it off for too long.

Before you start thinking about signal-blocking wallpaper, you'd be better of running wires. :)