Network Shaping Through A Server?

I recently upgraded my AT&T dsl connection from 3.0Mbps to 18Mbps and I'm ready to fully optimize my network. Some bandwidth intensive programs, such as netflix and youtube, can hog all that bandwidth relatively quickly, so what I want to do is limit/reserve bandwidth to each individual computer on my network so online games and latency-oriented programs still function at an acceptable level. I have my connection running as follows: modem (controls dhcp) --> bridged connection server pc (2 nics) --> router --> every other device on the network. It all works beautifully except my router doesn't have QoS software on it therefore, I can't do the limiting there. Is there any way to use the server pc as a network shaping device, controlling downstream traffic? I've googled and come up with nothing definitive as people don't seem to do this very often.