How do I transfer songs from "Music" app. on my ipad (songs I uploaded from itunes on my iMac) to Garageband on ipad??

Try this:

http://help.apple.com/garageband/ipad/2.0/index.html#chsb3f15dc4

Import a song from the Music app

You can import songs from the Music app on your device into Tracks view. You can import a song to an existing Audio Recorder or Guitar Amp track, or have GarageBand create a new Audio Recorder track for the song.

Songs imported from the Music app do not follow tempo changes you make in GarageBand.

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Import a song from the Music app

• To import the entire song, set the current song section to Automatic; otherwise, only the portion of the song that fits the current song section is imported.
• Tap the View button to open Tracks view.
• Tap the Loop Browser button in the control bar, then tap Music.
• You can search for songs by name, or browse by album, artist, genre, or playlist.
• To preview a song, tap it in the list. You can control the preview volume with the slider at the bottom of the list.
• Drag a song from the list to Tracks view. Align the left edge of the song with the bar or beat on the ruler where you want it to start playing.

After importing the song, you can make the song section longer, then resize the imported region so that more of the song plays.

You're welcome! 🙂

The sunshine is very welcome after so many rainy days! I hope it will keep 🙂