Sweeney Todd-- I need to find the track to Green Finch and Linett Bird( the same one from the movie)on karaoke

I need to find Green Finch and Linett Bird by Stephen Sondheim. I need the short verision, the one they did in the movie. I would like to have an instrumental or karaoke track for this song. I'm trying out for a talent show and I can only be in it if I have a karaoke/instrumental track. Please, no vocals in the background. I cannot spend more than $20 on getting ahold of this track. I can use a file, too. I have iTunes, Windows Media Player, Quicktime, and I'm fine to download more- if necessary. Please give me a website, or something I can download, because I REALLY need that track! Thanks.