Macbook cannot connect wirelessly to Linksys WRT-320N router

[rws762]

I just purchased a new Linksys WRT-320N (as far as I know version 1, no ver # after model #) router to replace a wrt54gs router that has recently been acting very flaky, dropping both wired & wireless signals. On our network I have 2 hardwired PCs, a hardwired IMac, 2 hardwired gaming systems and a Macbook. I can connect all the hardwired devices but cannot get any wireless signal at all! The indicator on the router shows that wireless is operating but the macbook cannot get a signal (if I connect a network cable I can however access the internet on my macbook. I tried using mixed, n-only and g-only, along with various methods of encryption. At one point I did get to a point where I was asked for a wpa key but the macbook kept saying the connection timed out. I did get a signal once using g-only and no security, but it was very slow only about 8 feet from the router. any suggestions, I'm about to tear out the little hair I have left!!