How To Restore iTunes to previous date- Broken Library

Hi all,

I have a mid 2010 MacBook Pro and recently moved my iTunes Library (about 100GB) to a USB external hard drive (Seagate portable drive) AND connected it to a 2T Time Capsule via it's USB port. All seemed to work for a few days and then for some reason iTunes started moving my songs outside of the iTunes Music Folder. Many albums were split between the old location and the new location. Some songs were in the old file and some songs in the new file location. Very strange. At any rate it's a mess and I want to restore iTunes to my Internal Hard Drive as it was before I moved it to the external hard drive. How do I do this? Cheers, Tracy.