Ok before you go throwing money at the problem care to try the following tests?

1. Can you run speedtest when plugged in to the router via cable? These kind of issues can also be caused by a shitty line and as speedtest is based on you wi-fi network plus your dsl link its worth ruling out.

2. Turn off all wireless devices in your house and speedtest again. turn them all on, download something on each at the same time, and test again. Any difference in readings here will be due to the amount of devices over the 1 data channel/lack of routers ability to process this data [ISP supplied routers are often not up to the job]. Experiment a little with location too. Do a test close to the router [same room] and in your den and compare the difference

3. QoS can wait, unless someones torrenting 24/7

Solutions:
1. If things are just as bad when wired in, chances are your phone line sounds really bad to talk on too. Phone the people you lease the phone line from - usually BT, but you may have to go via whoever you pay for the line rental. If things behave properly - ie sub 50ms worst case scenario then chances are test 2 also made big difference to performance.

2. If this had the biggest effect on performance then this is your culprit. options are listed below in order of preference but some may fit specific issues better than others, with the exception of option a.

a) cable in every possible device, or just the one(s) that bother(s) you most. The more the merrier, if you can wire them all fantastic.

b) expensive, but you could upgrade to a wireless n MIMO router / access point. These can sport upto 4 channels, which would cut your problem by 4 providing you have the matching wireless adaptor on the client devices themselves. If you got a 5ghz example you would be in an entirely different frequency spectrum to the majority of your neighbours, bypassing the majority of interference issues too.

c) play with the frequency settings as suggested above.

d) bigger/more powerful aerials/transmitters/relays theres lots of options to deliberate over in this subject but thats for later. If your router has a location option in its config pages, set it to USA - there are different rules on the emissions of the antennae across the pond [they can pump out more signal]

Homeplugs are fine as long as they are on the same phase. unless you own a mansion or live in an industrial unit you'll just be using one anyway, so don't worry.
The most notable issue with using different rings is the drop in bandwidth due to longer cable runs.

Yah, I made sure it was my wireless. I'd be playing 6v6 by borrowing the router and connecting directly with an ethernet cable, but constantly moving the router around and leaving other people without net while I game wasn't a long term solution. I was also running a ping test to my router, so it was apparent the issue was between my PC and the router and somewhere along the line to google.com or something.

If I had control over the number of people using the router or the position of the router this would all be a lot simpler, but I don't. I even have a ethernet cable long enough to run all the way down from my room to the router, but quite understandably my parents don't really care for cable running around the house.

Anyway, it doesn't matter much now. I splooged 40 quid on a homeplug from Amazon, it arrived this morning and took me about 5 minutes to setup. Appears to be working given I'm here typing this. I'm getting between 4 and 5 ms to the router which is fine. So far no dropped packets or random spikes. Pretty pleased with it atm, have to see if I am still pleased in a week or so .