I've used
senuTi before with great success. Used to be freeware but I think it's shareware now. Still worth paying for though.
https://www.fadingred.com/senuti/Is the music all ripped from CDs or do you have any iTunes purchases? ITunes allows you to re-download previous purchases on other devices if you log in to the same iTunes Store account (Apple ID).
AFAIK it's not possible to manage your iPod without using iTunes.
Did she not take a backup of her previous iTunes library before coming back? If she had she could have just copied that to your windows machine (in the 'My Music' folder), download iTunes and authorise it on the PC.