Connecting Wireless Router to a Linux-IP-Masquerading based network

Did a quick search and couldnt find the answer. Really appreciate your help.

I currently have a local network with my Linux machine doing the routing/IP
masquerading for other PCs.
The setup is like this:
eth0 : Static IP of my DSL modem
eth1 : 192.168.0.1, connected to a switch.

Other PC's and a Wireless access point all connect to the switch and
everything works hunky dory.

Now, to upgrade, I got the latest Wireless router (a+b+g) to replace my
access point and the problem started here. I dont see a way to connect this
wireless router seamlessly into my current network. I would still like the
Linux machine to be connected directly to the dsl modem and be the router
because I like to telnet/ss into my Linux machine from outside. The Wireless
router tries to do what my Linux machine is currently doing and the
manufacturer documentation doesnt provide any way to defeat this. Ideally,
I want the Wireless router to be a way to expand my current network. ie., I
want the router to be connected to my switch and the 10/100 ports in the
router to connect additional machines.

Have you experienced similar issue before and how did you get around it?

thanks,
SF91