It was ended because there wasn't enough manga material for it to keep going. Right now Chapter 52 is coming right now. So if another 25, they'd have caught up quick. They didn't want to put filler either.
Last i'd read we'll see season 2 in summer 2015.
The author said he'd like to finish the entire story, so then the anime will tell the entire rest of the story to the end next time.
He'd recently said that originally he was going to have a shock ending, but now in wake of its popularity, he's dropping the idea of doing it.
Though sometime this month or soon there'll be an OVA. If it's what i think it is, we'll see a titan talk for the first time.