How do I delete a facebook account from my notifications that I don't want to be integrated to on my computer anymore?

The notification center is telling me I must delete the account first before I add another account, but I cannot find, for the life of me, how to delete that account from being integrated on my computer. My friend got on facebook when I first had Mountain Lion and she accidentally selected to integrate it when she logged on to her facebook- before that mine HAD been integrated before. I've logged back onto MY facebook, but it hasn't asked me if I would like to integrate that instead. Help! I'm getting notifications from her page!