What's the easiest way to retrieve lost music files?

I was using a file sharing program and I saw that all of my music files were being shown in its share folder, and I did not want to share them. I assumed the files were duplicates and deleted them. When I realized the actual files were being deleted I stopped it, but not before several hundred files were lost. Here is the error message I get when I plug in my iPhone.

http://i174.photobucket.com/albums/w91/Candyman_8877/Untitled1.png

It says there is a hundred files missing, but when I count the "!" marks in iTunes, I got to 100 by the letter C, so there is definitely several hundred files missing. I have my machine backed up with time machine, and I also have a faily recent copy of my music folder on an external drive.

I'm wondering, what is the easiest way (using the fewest clicks) to restore all of my missing music files? I'm trying to avoid searching out and restoring every missing file individually, as there are hundreds and this would be very time consuming.

Thanks for any help and advice,

mcfada