Bartender Geek

I found what appears to be the entire song in RealAudio format on this site (search the page for "im ein", or just click on this to launch the RealAudio directly). It's sung by a man named Ross M. Levy. I don't know for sure it's the same song you're learning, but it's at least got the same title, and I listened to the first twenty seconds or so of it and it sounded like a kids' song.

Hope this helps.