You could try and get some antenns for your router to increase the signal output. Pick some up at compusa and if you dont notice a better signal/speed then return them. http://www.compusa.com/products/product_info.asp?product_code=316832&pfp=BROWSE
If the antennas dont do the trick then you could get a new wifi card. This would be great, http://store.yahoo.com/justdeals/nl3054cbplus.html, 200mW means long range line of site for these can be up to 4200-4300 feet.