You don't need ICS if you're already connecting through a router. ICS would be overkill and unnecessarily complicated (secondary network, DHCP server, firewall, etc.). You just need a bridge.
Patch the ethernet port of the VOIP adapter to the ethernet port of your laptop. Then go to Network Connections (Start->Run, type "ncpa.cpl" (no quotes) and hit enter), select the two connection, right-click, select Bridge Connections, you're done.
Of course, for the long haul, you'd be better off to just buy an inexpensive, standalone, wireless ethernet bridge.http://www.newegg.com/Product/Product.aspx?Item=N82E16833122432