Open up Garageband and start a new project.
Drag the Midi file into the project.
Click on the "View/Hide" Track Editor button on the bottom left side of your screen.
This will show the piano roll by default.
Click on "Score" to show the music notes.
From the menu at the top of the page, click on File.
From here you can edit the MIDI by clicking on the area you would like to cut and use (cmd t).
Press Edit-> Split
You can also join different parts of the midi with (cmd j)
Now you are ready to print your sheet music!
Garageband does all the work for you! :)