BleepingComputer.com: Transferring connection between networks?

Hey all. Ive been at this all day, and Im no computer expert so maybe you guys can help. I just bought a new desktop and want to run it wirelessly and securely as possible. I have a main computer emitting a WEP secured connection. What I want to do is get rid of this WEP network and replace it with a WPA network. I forgot the pass key for the WEP connection so I cant set up my new comp to that one.

I already tried making a WPA network and my new comp recognizes this WPA network in its "network manage" but when I try connecting to this network the only networks that pop up as options to connect to are my old WEP network and "default"(which I dont want because it has no security at all). So I guess my question is How do I transfer the connection from the WEP network on my main computer to the WPA network on my main computer so that I can get my wireless WPA feed on my new computer? Hope that makes sense. I need some help. Nearly punched a hole in my wall this aft LOL.

All the changes have to be made on the router itself. What is the make and model of the current router being used hooked up to your desktop?