Entering tracks into GarageBand

Because I'm a baritone vocalist, I often transpose sheet music from written before printing it. I have also been using pdftomusic to make a midi for importing into GarageBand. The method does not work very well and I have only been using the melody line for practice. I would like to have the accompaniment as well, on a separate track, so that I can also practice with the accompaniment alone.
Considering your talents it would probably be doable for you to enter each track using a keyboard, unless you know of software that would do it accurately and quickly. Another possibility is to find a midi that would be appropriate.
Attached is one of the songs that I'm practicing. I actually sing it two octaves down, easily transposed using GarageBand. Please let me know if you're interested in entering the tracks into GarageBand, and whether you could do it in under two hours. I have many sheets of music, so it could develop into a significant number of hours.
Best regards,
Sylvester Johnson