iPod - retrieval of nonpurchased music

My cohort used her office computer to download music from CD's that we had purchased onto iTunes to transfer onto the school iPod for school use. At the end of the school year in May 2012, our school received new computers. She moved to another school. So now I have an iPod with nearly 200 songs downloaded from our school CD's, but I am afraid to add another song because I fear losing all the songs on the iPod.
Do I need to somehow remove those songs onto my computer and then download them into a different iTunes account that I can access?
Is it true that if I plug it into the new computer with a different iTunes account that it will delete all that is on the iPod since it was on her iTunes account?
I do not have any purchased music on the iPod, only Cd's that we had purchased on our own and not through iTunes.
Thank you for your assistance in this frustrating situation. I would love to start adding more songs.