Know this name: DD-WRT
DD-WRT is a firmware updater that supports a large range of older routers allowing them a useful range of features as well as use with newer forms of security.
http://www.dd-wrt.com/site/index
These firmware updates require no drivers, no special software. Once installed they can be managed from any browser.
Yes, the wi-fi will still be the old speed ... but dropping $10 (or less) on a good 54g router at an estate sale to get second life as a repeater or bridge here and there in your home rather than a hundred plus on fancy four to eight antenna routers will pay for lots of Starbucks.