Belkin for xbox to connect to linksys with internet?

I have been using a belkin wireless router successfully to connect to my linksys wireless router and modem with the internet. Everytime I move I have to do the whole setup over again which causes me to get a headache and to get pissed off. I realize that my IP address for the modem changes.It is a pain just to get the linksys router to work again to have uninterupted internet service. I have to redownload Shivering Islaes to get content that will not load. I know that is the only way I can get it back again when I load the game. Anyway I always forget how to reset everything to get internet to access xbox live. i am computer iliterate but i have some idea about the various isp adresses and the pain it can cause to set it all up. i figured as long as i use the linksys address and default gateway and dhcp is enabled while my computer is offline it would work. do i have to call comcast to allow my xbox to be online or do i have to configure belkin again or what??? why cant this be easier