When is Kingdom Hearts 3 coming out? (Australia)?

I do not mean Kingdom Hearts: Birth by Sleep (which is by the way a kind of side game, but is necessary to understand the story). I already have kingdom hearts 1 & 2 and Birth by Sleep and heard that the 3rd one was coming out soon. I also heard that there is a Kingdom Hearts 0 coming out which is the prelude, is this true? And one more question. Is there going to be a sequel for Kingdom Hearts: Birth by Sleep? Because the storyline kinda of seem unfinished.