Port/IP priority?

So here's my deep thoughts I had tonight. I regularly play WoW with a torrent running. Although the torrent won't use much bandwidth(25% of my connection speed) I get significant lag. Even setting my upload/download to 25% of my max connection I get bad lag when playing. It's also intermittent. 1 second it might be 150ms, next second might be 1000ms. I am currently trying to isolate the exact problem.

So I thought to myself that maybe if I could give data for WoW 'priority' over the other data, maybe this would help with this nasty effect. I use a Windows 2003 server as my router with NAT and a basic firewall. I was thinking that since I know the port and the IP the data is going to, it can't be that hard to give that data outbound priority when I play WoW. Is there any 3rd party application, or a feature in Windows Server 2003, that let's me give ports or IPs priority over other data? If not is there any other way you recommend I try to combat this problem? Just thinking about this idea would make me think that alot of torrent lovers would want a program like this so they can surf the net(port 80) without having to fight their torrent for bandwidth.

I went searching with google and all over Tom's Hardware Forums looking for something like this, and I can't even get a name of anything like this. I really don't even know where to begin to find any kind of tool that will let you do this, assuming it's possible. All the searching only turned up stuff for QoS for VoIP and the like. I'm willing to bet money someone has already developed a program to do this, but I have no clue what to even call it. Searching for "Port priority" doesn't turn up anything helpful that I could find.

Thanks in advance!

-Cyberjock

Do a google search on Microsoft qos configuration and see what it hits.