Bogie, this is old hat, but keep your eyes open for a Linksys WRT-54G, versions 1.0 through 4.0.
They run Broadcom CPUs, and have enough memory to run either DD-WRT or Tomato firmware.
These firmwares replace the original Linksys Linux kernel with something considerably more powerful.
Then you can tailor your bandwidth per IP address, run QOS filters, and a bazillion other options.
This is a screen capture of my router's internal Tomato pages, note that I have bandwidth prioritizing in this screen:
http://mauser98.com/tomatoqosbasicsettings.jpgThen I can further classify what ports or IP addresses get a given share of the prioritized bandwidth:
http://mauser98.com/tomatoqosclassification.jpgI can view bandwidth usage that the router stores in either real-time or 24 hour graphs, or lists as daily, weekly, and monthly values:
http://mauser98.com/tomato24hourbandwidthgraph.jpgI can also just plain shut down a given computer's Internet access on the home network, simply by setting up access restriction rules. The first one I have here is because one person decided to use Limewire after I told him not to, making for a very chatty network with a bazillion open ports inviting evil things into our side of the firewall. I shut him down between 11:00 PM and 4:00 AM:
http://mauser98.com/tomatoaccessrestriction.jpgIf this sounds or looks too involved for you, let me know. Just find me one of the cheapo Wireless G routers I listed above (eBay has tons of 'em) and I'll flash the software onto it, then mail it out to you posthaste. You can leave your home network in the usual 192.168.1.1 address range, or do something like the 10.10.10.1 range I use here in deference to my wife's VPN tunneling to her office computer.