How to transfer songs on your ipod

Hello,
Recently, we threw out our old computer, which had all the files for my songs and stuff. So now we got a new computer and I downloaded another iTunes on it, but the problem is, most of the songs on my iPod Touch 4 are burned from my CDs, but I sold the CDs thinking I wouldn't need them since they are all on my iPod (so since they're not purchased, I can't do the transfer purchase thing). But whenever I try to sync the music and apps and stuff on my iPod to my new iTunes, a sign pops up saying that the stuff on my iPod will be deleted. I've already tried the manually manage music and videos-create playlist with songs-pick the playlist then sync thing, and it won't work. What you need to know is that my iTunes has like only 10 songs that I bought. So when I click on the music icon then try to click on the playlist that i want, there is none. Please please please... what do I do????