Best way to set this up.

this is what I have, what is the best way to connect it all of them together?
I have one Cisco 7500 router and 2 core Cat 6500 switches; I need two networks one .com the other .net. I do not want the traffic from the net side to interface with the.com side the .com side is the adman business side. I know Acls on the router will handle that part, but what I need is the best way to setup the system so I will have the most bandwidth per each side. The .net side will be hosting.
This is all hooked up to a T1 line from Sprint.