Well, this is all my /etc/resolv.conf says
i.e. the DNS IP's for my provider.
I'd imagine that you'd just use the IP of your wifes PC for the default gateway, as mentioned above.
But if you don't want to take hours compiling the fluxbox or whatever, you might want to check the gentoo doc's site and more specifically the portage docs to see how you'd check for any precompiled binaries for fluxbox etc (or even if you have the second disc, the one with the GRP packages on it, you could disconnect from the wifes pc, then mount the disc and do emerge -k fluxbox to see if you can get that - it's a hell of a lot quick to get up and running).