|I changed a few things in your post. Some of that info you don't really want to advertise publicly.|
Having said that.
Start with the Linksys router disconnected from your network and ensure everything is working properly on the Westell.
Once you're satisfied everything is working ok, check the DHCP settings on the Westell and make note of the DHCP Scope (usually it's 100 to 199 on most SOHO Routers).
Then, click on my name above, read my "how-to" guide on adding a second router. You're going to want to use the version where you connect LAN port to LAN port (ie: LAN port on upstream to LAN port on downstream).
Once it's connected and working, and clients plugged in to it can get an IP from DHCP, then configure your wireless network using WPA encryption.
If you are a DYI'er, then my guide should be all you need to get the second router, and it's wireless network, working. I get the feeling you didn't even look at it....