That's more than one year already. Then they have to make the game itself.
Several might have been a little farfetch'd (:D), but I'd say two years after the end of the anime.
Well, if you think about it, the OAV episode JUST came out, so technically the anime hasn't really been officially over for too long now. xD; Plus, if they're planning on releasing the game late this year, or whatever.. maybe they're planning on giving the series another anime release between now and then?
It's true, I can't seem them releasing the game late in the year, while the series itself gets nothing new added on it between now and then. >_>
Then again, the manga is still releasing, I believe.