you can spend a couple of boat bucks and get marginally better results or you can buy the alfa adapter and get really good results. been using this one for two years and it vastly exceeds my previous (expensive) adapters. it comes with a short antenna but for a few bucks more they will sell you a larger antenna and cables to connect them so you can put the antenna higher up.

this is a really easy dongle to install. it needs TWO USB ports because it has to draw 500mw from your computer and each one only provides 250mw - or so i'm told. just plug it in and play. works great. can't go wrong for under $50. it came recommended to me by a computer geek sailor and i've been very happy with it. best thing about it is you don't need to be a geek to use it.

they also make one that's rated at 1000mw but I THINK that it needS FOUR usb ports. just check amazon for the alfa 1000mw to get more details on it.

http://www.amazon.com/AWUS036H-Wireless-Adapter-Network-Antenna/dp/B000QYGNKQ/ref=sr_1_4?ie=UTF8&qid=1288663074&sr=8-4