Router to router wireless connection for 360

Hello,

first off i would like to say that what im about to ask is something that i learned and heard about. im learning to use a router to a router wireless connection for an xbox 360 to get onto xbox live. For those that do not get what im saying is that instead of buying a wirless adapter for $100 at bestbuy or something, i learned that you can use 2 routers to make a connection to connect to xbox live. So my question is how can i use 2 routers to make a connection to my xbox 360? my uncle try to help me do this do but he said i dont have the right kind of router to do it but i think it can be done with the one i have. i have a main router already and a secondary router as well. i tried to resart my 2nd router and turn it into an access point to see if that work. i think it will work but every time i put the router in my 360 is saying that the network is not connected right or the ip adress is wrong. i think i have but i just cant get the network to connect automatically! if you need info on the 2nd router im using here it is:
model: belkin54g
Wlan/lan mac address: 00173F56E3AA
Wan Mac address: 00173F56E3AB
serial #: 20064206169
ic: 3623A-F5D7230C
ver. 6002
model #: F5D723O-4
FCC ID: K7SF5D723OC

If any one can please help me do this step by step i would greatly appreciate it because i tried figuring this out like forever and im getting annoyed with it! Im getting to the point to go buy the 360 wireless adapter but i dont feel like wasting a $100's on a little thing such as that if there is a cheaper way to getting on xbox live!

Thnx!