unstable wireless connection netgear router

My girlfriend just got RCN cable internet and a netgear wireless router. Her roommates pc works fine with the wireless but she is constantly losing and regaining connection. It seems weird though becuase she never has a signal thats below "good"

it pretty much gets a connection for a couple minutes, then loses it for a minute or so, then gets it back- over and over and over

She has a toshiba laptop with a built in wireless card, win xp, and the network is pasword protected
(her roommates laptop might have vista, i dont remember... def windows though)
sorry i dont have more info for the router

she is a bit further away, a couple walls to pass through... could that really be enough to cause this problem?