Network Connection Problem

We are attempting to connect our ASTERISK server to another network, outside of our limited/Comcast network. We are on a 192.168.x.x network with WAN service being provided by Comcast. We are attempting to PING,TRACEROUTE,call by SIP to a Vorizon network 75.200.x.x?

Our network configuration is fairly simplistic we have the following:

Comcast router providing External WAN connection

               connects to

      8-port Linksys router

             connects to

            our CPU's.

We are NOT running Firewall or NAT YET!!! Want to get the connection done first.
We do have DNS up and running
I hope this is enough information for you to help us?

How do we make the final connections to outside networks?