I think the children deserved it and were incredibly stupid to start a fight they should have knon they couldn't win.
A similar thing has happened to me a couple of times in my life: Once a bully set his little brother on me, I pinned him to the ground and banged his head on the floor, the bully then punched me in the face, knocked me down, then left. Another time a kid half my size started on me, again I pinned him to the floor and told him I'd kill him if he tries to fight me again, his older friends came over and threw me in the prickly bushes.
What should you have done in the first place? From what you've said, the kids were just being annoying at first and not actually doing any harm; is this true? If so you should have ignored it, the chances are they would have got board.
If they persisted and started stoning your cats, you should have threatened to call the police if they didn't stop. If they carried on, then you could have used 'reasonable force' to expel them from your property. I take it this is your house, flat or rented accommodation? I don't know what the law is where you live but here in the UK you're allowed to kick people out of you house as long as you don't deliberately harm them, from what I've gathered in the US it's more relaxed, you can shoot them if they refuse to leave.
What should you do now?
Watch out for their brothers or fathers and try to remain calm if you end up in a confrontation with them.
I'm probably not a very good person to give advice on the matter. I'm all right talking about it but, like you, don't always do very well in this sorts of situations.