It took a bit of work, but I was able to move the modem/router/VoIP equipment so that the wi-fi now reaches the one bedroom. Unless there's a connection hidden inside the spray-foam insulation, (which is still a possibility), there was only a single, unbroken length of coax wire running from outside all the way downstairs and then upstairs through to the cable modem. We may still end up getting a stronger router after all; we'll see.
I finally got my worker profile live on oDesk, initially to sell voiceover services. (I've been a client there for two years, but they maintain separate profiles for each role.) I started off by applying for four voiceover gigs.