Nope. There's no way. Almost no consumer level routers have any features that will let you control the bandwidth either in to or out of them.
Is there a FAQ for this kind of thing yet? It seems to get asked on a very regular basis.
You have 2 real options to control the bandwidth on your network if the specific application in question has no bandwidth control built in. First, you can use a linux box as a router and make use of the QoS software on it. Check out
www.lartc.org for the howto. It's heavy duty stuff but there are cookbook solutions available now that can make the process of controlling your bandwidth a lot easier for simple cases. This is what I use at home.
The other option is to buy a professional router/switch that has QoS capabilities built in. I'm unfortunately not too familiar with affordable ones. Most any one with QoS will probably be way overkill in every other way and will cost quite a lot more than consumer routers.
There are some hacks that you can do to the Windows TCP stack and parameters that you can change to make it much less efficient (ie use less overall bandwidth) but I wouldn't recommend them.
Gaidin