Where can I find the critical iTunes files/settings -- transferring data to new HD

Hi -- I recently installed a new internal Seagate 1TB SSHD drive into my MBP 15" Late 2011 to replace the OEM 500GB internal HD. Did a clean install with OS X Recovery. So far so good. But I didn't transfer over the iTunes settings + whatever files are the formats of the music I've imported into iTunes. (due to previous space constraints I took the actual mp3 files and put those on an external previously and just left the iTunes version of the files).

I should have all the relevant iTunes files on on backup drive -- that is I transferred all the system files to the external drive.

Would someone please let me know the names of the critical files for iTunes -- I'd hate to have to start over and import the music and the cover art and all the rest of it!

Also if you could tell me where these files actually reside (i.e. what folders, etc). Thanks!