here are a few wi-fi homebrew antenna websites

take that crappy rubber duck off of your wireless access point, spend less than 10 dollars, and make yourself a more efficient hi gain (23dB!) out of such things as pringles can, baked bean cans, old directv dishes, chicken wire, many different models and variations, none seem too complex to build for anyone even slightly crafty.. what do you have to lose? perhaps that deadspot in the driveway, or basement guest room hopefully~

there are several here including the "bi-quad" http://martybugs.net/wireless/biquad/

this site lists 4 antennas, construction, comparisons, photos, and MORE links:
http://www.saunalahti.fi/elepal/antennie.html