Connection Woes

Being a web and software developer, I spend a lot of time in front of my computer. Every so often, it is nice to be able to take a break. My distraction item of choice is my XBOX360.

I have used the XBOX Live service for some time now, but for the last 4 weeks, my connection has been awful.

My XBOX360 is connected to my PC, which is connected to a wireless network. There are 3 other machines on this wireless network too.

Whenever I do an "internet connection speed test", I always get good results. I have almost 2 Mbps coming down the cable internet connection and 185 kbps going up.

Occasionally, one of the fellow house-mates will download some music or stream a TV episode, so I can understand why things may appear sluggish at those times. I also have another house-mate who constantly seeds torrents, but that is limited to 5 kbps.

Is there a way to configure the wireless router to give my XBOX360 traffic the same priority as regular internet traffic (so I get an equally strong signal at the times when connected to XBOX live)?

Is there another issue that is ensuring that I have the worst imaginable gaming experience?

This is a genuine plea for anyone with knowledge in this sort of thing to contact me.