Again, you haven't seen the last of Bonnie's grandmother. In fact, her most recent appearance has been during this current season. But that's the great thing about TVD - so few characters are ever truly gone forever. Although, as I say that there certainly are ones who are - or at least the producers
say they're gone forever...
And as much as I loved the first season, I love the second season even more. There are some radical and, IMO, fantastic changes made during Season 2!
But again, that's all I'll say...