iPod How do I get songs from my Iphone back into my Library?

[nvjusme]

The folder that I had all my songs in for Itunes was missing everything from letter D to Z but everything would still play perfectly fine in Itunes. I was concerned about not being able to see these files so I copied my backup over from an external hard drive and then replace the bad folder that only had the artists from A to C.

Now, I can't find certain songs that I paid for through Itunes anywhere in my computer, including the waste basket.

It seems like maybe my hard drive was becoming bad and it wasn't reading that sector of the drive or maybe Itunes is just trippin'.

Any ideas?

I have stuff on my Iphone that is not on my Itunes. How can I get that stuff from the Iphone back onto my Itunes Library?

thanks