Get a Linksys WRT router and flash the DD-WRT v.24 firmware in it.

DD-WRT is a linux-based firmware that gives more options and features to the user. My friend suggested I should get this firmware when I was getting problems with my Linksys -- I have not used it. He has and he likes it and it works the way it should.

dd-wrt Home Page
Hardware Support

Wireless Mode: Repeater

Give it a try?

p.s. fixed my router problems by flashing the newest release of the Linksys firmware.