Editing itunes music with Garageband

Hi,
I am making a slideshow using a song purchased via Amazon that is in my itunes.
I want to remove a large section in the middle of the song.
Can I do that with Garage band? I tried and was unable to even import the song...
If it is possible, please give easy-ish directions as I've never worked with Garage band before.
Thank you very much!

Oh, and I'm using a macbook pro purchased in 2011.

If you cant import it try Audacity: Free Audio Editor and Recorder as i know you can with it.

you can also edit the audio and cut it within iMovie and most other video editors.

I tried Audacity, but it won't import...

Can you please explain how to edit it in imovie?

Thanks, y'all!

I dont use iMovie, but there are extensive manuals on apple's site and plenty of youtube videos covering the product.