How can I take a shared calendar and recreate it using my personal ical rather than having to share?

Here's the deal. I stepped into an administrative position last fall and began building an entire calender schedule for our summer 2014 program. I put a lot of work into building two months, however I have only just realized that the apple ID is for the former person who had my job (she left herself logged in on the mac I am now using). My fault for assuming the apple id and login would be the same as the email account I am responsible for.

I did manage to share one of the calendars I created using her apple ID, so I still have access, however, I'd feel better if I could somehow take this "shared" calendar and keep it as my own using the apple ID for the email account I'm responsible for. In other words, is there a way to take a calendar that was shared with you by someone else and save it under my apple ID as MY primary calendar? I'm paranoid that this former employee will delete said shared calendar and I will have to start from scratch...