Tough Wireless Network Problem?

I have an HP dv5220 laptop purchased August 2006 which uses an IPW3945 ABG card(intel), which has been working fine until the past 2 weeks. OK before you start bashing me, I've been stealing a neighbor's wireless for a while now, but I ordered internet for myself, which is about to come Sunday . But I still want to ess the problem and figure out why my wireless isn't working. so 2 weeks ago, my wireless went haywire -- it still works but it is verrrrrry slow, i mean as slow as dial-up. At times, it peaks to regular cable modem performance though. I identified it as a linksys WRT54G wireless router (through entering the gateway IP in the web browser). It isn't a problem with the network card because i tried connecting to another router and connection performance was good. So now that i pinpointed it to the router i've always been using, I tried to figure out what it is. I'm not a network specialist so could someone help me? Im switching to Backtrack2 livecd to use wireshark.