I have loads of info that I work on modems and routers that I would like to add to a site.
So here is the latest available info on making a biquad and using it in a WRT54GL. And comparing that to a standard billion adsl wireless modem router and a later N wireless router.

Biquad is a simple antenna to make. The reference antenna.pdf shows how to make one from your existing 2dbi antenna.
And is just a variation on martybugs method. http://martybugs.net/wireless/biquad/