Ipod info to new i-tunes

[Geddes]

I had loads of info on my old pc (i-tunes) which some is on my ipod classic, and now i have a new pc which is up and running, on the new i-tunes it's blanc but i still have info on my ipod. How do i transfer all the stuff from my ipod to the new i-tunes without deleting or starting from new?