Cisco Switching/Routing :: Module To Add Gig Interfaces To 2800 Series Router

I am trying to add WCCP to be configured for websense. My first option seems to be either purchase an IPServices license for the stack of 3750E switches, but i am thinking this will require us to license all three switches in the stack. The second option i am looking at is to do the WCCP configuration on the 2800 router we have on the edge. The problem is both Gig ports are in use, one going to the firewall and the second going to the ISP. My first question would be, which option is better in terms of manging as well as cost of implementing it.The second question is, if WCCP on the router is a better option, what is the add on module i should be looking to get to add the additional ports to hook up the Websense cache.