Sorry to hear it, that is bad news.
They don't have to give you a reference and they don't have to give a positive one if they do, they can leave it quite ambigously. If I was you, I wouldn't put them down as a reference, as in the next company can phone them. I would also leave the reason that you left as open as possible; don't actually say you were fired, but you can say that there were differences of opinion. But will they actually fire you? Usually companies will avoid that and just give you the option to leave - as in, you will!!
Good luck with this!

Tash