I just checked TVLine's renewed or cancelled list, and they have it down as a sure thing. So it hasn't been officially renewed, but they're pretty sure it will be.
As for whether there is still enough story for a 3rd season, I think it's still to early to tell.
Yea, they're talking about the Spin off airing between seasons and the article mentions it's a top rated show, so, it's pretty clear they have no intention of ending OUAT any time soon
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?