With Attack on Titan only being 25 episodes, we can only wait and be excited for season 2 to come out. The manga is currently being worked on which is great because there are so many questions unanswered after episode 25. I was worried when it finished if that was it and they just left a lot of things out, but the fact that they are continuing means that I have something to look forward to.
I have no idea when the release date for season 2 will be, but considering that the manga is still being worked on we can assume it won't be for a few years. Probably late 2015 is my guess. While that doesn't matter as much because we know it's coming, we can be happy to know our run with Eren, Mikasa, and Armin isn't over yet. I'm excited to see what's next!