Wireless Speed Oscillations / Can't Connect To Game Servers

Living in a student house in the UK, under Orange ISP in central Manchester. My 5 housemates are connected wirelessly to the same router, and are all receiving much faster download speeds (2 megabytes per second etc), and consistant connections than mine (which goes up to 2 megabytes per second, to under 1 kilobyte), yet they may be further away in the house etc.My wireless connection speed varies, changing every second between parameters 54.0mbps, to 1mbps, and ping on ventrillo VoIP software going between 16 and believe it or not, 16,000. I've tried changing the wireless channels, but still no luck, as for connections to game servers, my internet is so bad I can't tell if I've got to do port forwarding/triggering (something along those lines), or if it's just too awful to connect full stop. I'll get to a log in screen, some games like HoN, it will say connecting to server, and appear to time out, nothing happens. Guild wars 2 however logs in, however the second I appear in-game it freezes and lags out.I've contemplated getting a powerline adapter, however if everyone else is getting better wireless speeds and having no issues what-so-ever, it may be on my PC's end, and I'll have wasted £30. A 20M ethernet cable isn't practical either, as student houses have forced closure fire doors which would chew the cable to bits in days, and if a drunk housemate tripped over it on the stairs, they'd rip the back of my PC out...