Problem Network Routing between router and modem.

Let me start off by giving the details of my devices. I have a Netgear CMD31T modem, and a Netgear WNDR4300 router with DD-WRT installed (06/23/14 build 24461).

My LAN is on 172.16.16.0, the IP from Comcast is 174.55.xx.xx, however the modem is on 192.168.100.1.

So basically, the LAN address of my router is 172.16.16.69 (anything below has a static IP and anything above is dynamic), the WAN of my router is 174.55.xx.xx; this is preventing me from accessing the status page of my modem.

I need help in setting up a static route that will allow me to connect to my modem's status page without having to connect my computer directly to it, and setting a static IP of 192.168.100.10, just to gain access to my modem's web GUI.

I am terribly sorry if this is in the wrong section, but it's not windows related (at least to my knowledge) and there aren't any networking sections to post a thread in.