How to make my wireless better for xbox live?

i have a belkin54g wireless router. and i have a really good connection but its not what it used to be. i used to have really good connection on xbox live and i could tell because i was always the connection host on call of duty world at war and cod 4. but i use McAfee Wireless Network Security program that puts a WPA code on my router and i am wondering if anyone can tell me how to make my wireless better through the McAfee program?