Windows 7: Sharing bandwidth with Xbox Live

I have two computers and an Xbox on the same network. The problem is when I'm downloading something on my computer (which is always) the Xbox usually can't even connect to Live. I understand being on the same network means sharing the available bandwidth but, is there some way to allocate or increase available bandwidth so I can dl and still be able to play live?

What router are you using?

I have a Westell Versalink 327w

Sorry I ran to the store for some groceries, but proactive is good :P

Is there a QoS option available?

I have Home Premium, I don't know how to get to the Policy Editor.
Gpedit.msc doesn't exist

Im saying in the router,
Log into to gui interface.

I'm not seeing it. My computer vocab isn't very large. Is the GUI interface where I type in my routers IP into my browser?

yes correct.
I am cooking dinner so i will be back and forth to help you out.

Thats fine, I appreciate your help. I have it open but I'm not seeing anything about QoS...