High Ping CS:GO

Okay guys, so I've been playing CS:GO since February 2014, it's the only FPS I play, and the ping is SO bad. No, there are no torrents running, but this happened rarely when my sister and dad were out of the country. WHENEVER someone is downloading something or let's say my sister is watching a video online the ping goes between 300-1200. It's just unplayable. 

Any advice? I'm with TalkTalk in the UK and speedtest.net gives me a ping of (approximately) 16 ms,  12 megabits down and 0.8 megabits up. The router is a Huawei HG523a and I have read about QoS but there are no guides on how to set it up for this router. I can't install DD-WRT on it either (not that I know how to) because my router isn't supported. This is what the QoS screen looks like 


Bump

You should first determine if this is the fault of the router; your networking hardware, the game or the server.

To begin with, are you using a wireless connection or Ethernet cable? If the former, why not try using Ethernet cable instead and see if your ping goes down?

Next, you could try using a different server that is closer to where you live: this should reduce ping times by decreasing distance between you and the server.

Then, you could always try a different game to see if it's just an issue with Counter Strike.

Finally, if all that fails; it's your router or your isp throttling you.

I did try using an ethernet cable, and although I found the ping to be spiking less often, when it did spike, it would still be to approximately the same level as mentioned in my original post - however, the fact that it spiked less often could just be a coincidence. I can't use an ethernet cable in my room due to the fact that only the master socket is activated and the one in my room isn't, and my father won't let me use powerline. Lastly, the ping is perfectly fine when it ISN'T spiking and no one is downloading files or watching stuff on netflix. Any comments? 

It's weird because we recently moved houses and in that house (also on Wi-Fi) I don't remember these massive ping spikes happening. Then again, we lived there for a short period of time. (Moved countries long story)