i want to transfer all my songs on my ipod classic to my itunes not just purchased ones

I just bought a new computer and want to transfer all my music from my ipod classic over to my itunes...i had to deauthorize my old computers because I got rid of them as I bought new ones but didn't realize I had no more authorizations left when I tried to add this new computer.

My question is I went to sync all the songs on to the new computer and it deleted all the songs but the purchased ones....is there any way to get back all the other songs with out re-downloading all the cds again?

Please help