make a playlist file for your shoutcast stream, and upload it to your site - then go to your admin panel / Menu section and add a link to the playlist file.. when a user clicks the playlist link, it'll launch whatever player they have associated with that file type.
another option would be to drop the link into one of the ad boxes through the themes > blocks section.. you can add
to the link for a poor mans pop-up.. maybe use an image in the link to make it stand out from the text that you're using now ;)