Applications :: Damaged ITunes Files - Starting Over

So the last couple of days iTunes has been hell for me. Couple of days ago, when I opened iTunes like any other time, I was presented with an error message saying my itunes library was damaged. Anyway, long story short, I've started over and created a new one and imported all my songs, podcasts, videos etc in. That all worked well, but I was still missing my precious play counts and ratings, though I was able to import my playlists. So what I did was import one of the itunes database files from the "previous itunes libraries" option. What happened then was that it removed all the files that I purchased after the date in which the database file was created. Annoying as I can't remember every song I've purchased.

The 2 main problems at the moment is that the files I purchased are already in my iTunes media folder, I found that out by just searching some songs I remember, but the matter of remembering each one is impossible. I contemplated the idea of "Add to library" but I think all that does is import everything again into the library rather than find any ones that aren't already in it. Is there anyway to get iTunes to automatically find the files that aren't already my library and just add those? Second problem is I have is the dreaded '!' next to many of my songs, again I am sure that I have these files in my media folder (I've checked), iTunes has just (for some reason) not found those files. Again, is there a way for iTunes to automatically find those files? As opposed to me finding and clicking on everyone of those '!'s and locating the files manually?