You'd rather just do it yourself. Look for the albums in the iTunes Music Store. Most of the songs you can find there. Otherwise the internet is full of tracklists. I suggest you delete all your music from your iTunes library, and import it again album by album, and that way you can organize and tag them all correct. This is what I did a year ago. I'm now at over 9200 songs, all 100% tagged. When you have a new album, just import it, tag it right, and then do the next.
I hope that helps.