What you need:
* An MP3 to split
I'm using Garageband '09 Version 5.1, but this probably works in a similar fashion with other versions as well. I don't see any reason to keep paying for updates of this program...
Step 1: Step 1: Setting Up
Once the project loads, hide the track information bar on the right by clicking the the blue "i" in the bottom right corner. Having extra space to work with makes this easier in my opinion.
Click on the music note at the bottom center and change it to the clock. This will make it easier to find where you need to split the track by changing the ruler above to show time.
Now drag and drop your MP3 into the blank area underneath the ruler and vocal tracks. If your track does not start at 00:00 on the ruler, simply click and drag to move the track to the left. Garageband should now look like the first photo for this step.
Step 2: Step 2: Split the Track
Now that the track is split, click away from the track to deselect it. The orange portions should dim. Now click on the half of the track that still contains the blank space. Just that portion will become bright again. Drag that section to one of the vocal tracks. Click on the speaker phone icon under Male Basic or Female Basic (depending on where you placed the track) to mute this portion for now.
Step 3: Step 3: Save the Song
Go to Share>Send Song to iTunes and select the My Info tab. Input the name of the artist, playlist, and album for export to iTunes. Make sure Compress is checked and Compress Using is MP3 Encoder.
Audio Settings has four options:
Good Quality: "64 kbps, Stereo, optimized for voice". This is very bad quality for a song track.
High Quality: "128 kbps, Stereo, optimized for music and complex audio". This is the lowest quality one should ever use for a song.
Higher Quality: "192 kbps, Stereo, optimized for music and complex audio". This is very similar to the quality of my song so I could choose this option but I won't.
Custom: Allows one to select a bit rate from 32 to 320 kbps. Exporting your song at a higher bit rate than what the original file was will not improve sound quality. Custom also allows one to encode in Variable Bit Rate (VBR). I selected 192 kbps VBR, as it is near the original track's bit rate. I kept Stereo selected and both Use Joint Stereo and Filter Frequencies Below 10Hz selected.
Hit Share and the song file is exported to iTunes. Even though I chose 192 kbps VBR, my song exported to 220 kbps VBR. I probably could have done 160 kbps VBR and have the same quality but a smaller file size.
You should now be able to follow the same process for the second song. The only major difference is you will need to rename the second track in iTunes after export.
Congratulations, it is no longer necessary to listen to Comin' Down before Lake of Fire!