you can get a usb wifi dongle with an antenna socket, then buy the relevent antenna,

or

this http://cgi.ebay.co.uk/28dBm-USB-WIRE...3A1%7C294%3A50


or depending on you wirelan card in your laptop upgrade the card, allthough the card in my eee was a 802.11n it was pretty crap, now have an intel 5350 card fitted http://cgi.ebay.co.uk/INTEL-WiMAX-WI...3A1%7C294%3A50

or mod your laptiop and original card to plug in an external antenna