2Wire wireless/constant disconnect

I'm a newbie to wireless networks, so be gentle!

I recently set up a 2Wire homeportal to my desktop in order to use its
DSL on my laptop. I installed 2wire's wireless NIC, and find that
while I can connect and surf the web, it disconnects me every couple
of minutes. I've heard interference can affect it, but even if I use
my laptop 2 feet from the homeportal, I still get dumped regularly.
Both computers run XP, and I use SBC Yahoo DSL. Can anyone help?

Matt