Dumb Question about wi fi

Hi,
I'm thinking of geting a Squeezebox (or similar device) so I can listen to the hi rez files resident on my iMac through my stereo on another floor. Sounds simple, huh? The problem is the wi fi in our house is created by a router hooked to my wife's PC. The iMac can see the wireless and this is how I get internet on the iMac. But will I be able to connect the Squeezebox (or any other music streamer) to our PC-based wi fi and then access files on my iMac? Or will I need the iMac to generate a wi fi network of its own?
Thanks for any help!