Newly purchased C3700 modem/router with existing Linksys router

Hello all,
I've looked at postings and read through the manual but cannot figure out how to make this work.
I had to upgrade my TW cable modem to obtain the higher speeds of my upgrade and chose this model.
All of my connected devices are connected to the Linksys router with addresses:192.168.1.XXX
The Linksys router is plugged directly into the C3700.
all the connected devices work fine, except I cannot access externally. I have one computer that runs a home automation system and a foscam security camera. I have a Dyndns service which I have added to the C3700 but I still cannot access either. The C3700 is somehow blocking all incoming traffic. I tried port forwarding, but because the C3700 uses:
192.168.0.XXX
it sees my forwarding to the Linksys router as an error.
What I would really like to do is turn this in to a modem only like the TW modem and turn off the wireless. I tried going into the settings and turn off router (under administration/Router mode) and then it made the C3700 inaccessible so I had to reset it. Anyone know how I can get this to work?

Thanks for your time,
John