Kurt Knutsson has some ideas for doing this. Luddite that I am, I question a couple of his going-in assumptions, at least as his suggestions apply to my case. Start with his subheadline:
Fix deadzones, speed up slow spots, and make your wireless internet signal reach farther
I have an ordinary-sized, one-story, wood frame, single-family home. I don’t have deadzones or slow zones (I’ve walked signal-assessors around my house). I don’t want my WiFi signal to reach farther, either; that would take the signal even farther outside my house, even farther past my city lot boundaries, making it even easier for wardrivers to capture, or for others to (try to) piggyback off my WiFi Internet connection (despite the several security precautions I’ve taken).