go to linksys.com and click on support and download the full user manual for your router. then find the homepage of the router IE http://192.168.0.1
and the default user name and password and go to the homepage and type in the user/pass to get to the settings of the router.
if you do not know the user/pass it may be because you changed it when you first set it up. you can reset it (also listed on the linksys site how to do this) but you may loose you settings for connecting to the net or keeping you computers connected to each other so reseting should be the last option used.
once in the homepage of the router you will be able to make any changes to settings you need even locking yourself out of the router and the net if you dont know what you are doing. the cd is used to do the bare minimum and in order to get you connected you can do a lot more in the routers pages than listed on the cd setup.
just remember if you make to many chages at once without testing to see if they work for you. you wont know what change broke or fixed your problem