Go to the cops buddy, you got nothing to worry about. It was very clearly self defense. It is your legal right to defend your self, your property or a third party, if you/it/they are under imamate or immediate attack, with equal or lesser force. Since there was two or them and one of you that is lesser force. And by them sayin "give me your keys" makes it very clear of their intentions. Go to the cops, I know that the VIC pol that I have dealt with in similar situations take it very seriously. Well, I wish you all the best with your recovery, and I sincerely hope that these guys get ass raped by someone.
Cheers
Helio