Thanks everyone for your help.

I'm pretty sure I've decided to upgrade to the Linksys WRT54GL
so I can upgrade the firmware to DD-WRT which gives me more control of the router and maybe upgrade the antennas. It seems the cheapest route to go and still get good performance. I figure it'll also be a good learning experience.

Also thanks for the BT info. I'll assume that was the problem since it only went down when BT was running.