I don't understand how you are having a hard time picking up a signal being only 30 feet away. I am 2 floors up from the router and I pick up full strength constantly.
ya we were learning about something like this in Calc the other day. Its like a 'repeater' and it amplify's the wireless signal for a fartehr distance, and I am assuming making the signal strength stronger. something like this, Linksys - 802.11g Wireless-G Range Expander - WRE54G but they are kinda pricey