Heya djrip,
Being the modem/router is single port, my preference would be to connect your DIR-655 to the NV5200 via the Ethernet connections and same from DIR-655 to your computer. Set up both the "Network" and "Wireless Network". I was with verizon and their modem/routers are pretty nice, but transmit rates are far less than the DIR-655. Now am with comcast and stuck with the same kind of router as you,, a single port. I get no connection problems from the "Hard wired" main computer and the other two wireless computers have a steady 300 mbps connection. follow sticky on settings for "300 Mbps"
Good Luck