Last Monday, I was walking my dogs down the footpath over the fields behind my house, when I suddenly heard someone behind me yelling "Maisie! Maisie!". I turned round to see two twelve year old boys (approx) in pursuit of two off lead dogs, one of which was fast approaching me and my dogs, growling and snarling. To cut a long story short, this one dog jumped on top of both my dogs in turn, still growling and snarling at them, with its body across their shoulders, until I jumped in between them (it was only jack russell sized, although I have to admit I was still quite scared) and snarled back at it.
Today, as I was walking back towards home in the same place and saw the same two dogs coming towards me, accompanied this time by a man and two young girls. I got my two dogs back on leads and this dog came tanking towards us again, with the man shouting its name which it totally ignored, and I stood as far to the side of the path as I could with my two dogs, hoping this other dog was going to go barrelling straight past, but of course it didn't. It stood directly in front of us, still, with it's tail straight up and then after 5 seconds or so it trotted over to my boy and leapt at him, growling and snarling again, with its front paws over his shoulders. My boy just tried to squirm away with his head down.
This dog then went off a couple of yards before coming back again growling and snarling at which point I tried to kick it and cracked it under the chin with my boot (yes, I did feel guilty and still do). It circled us again and then to my surprise, stood some way away looking at my boy wagging its tail. Immediately, this man who I presume is the owner caught up and his daughter behind him said "Shall I put her on the lead?" and he replied "No, she's alright" before giving me a smile, whilst I am still frozen to the spot I was in when I kicked his dog, and walking straight on without another word. The dog then followed him and off they went, whilst I went home slightly shocked and shaking, to check my dogs over and ring the dog warden.
Now, the things I'm unsure about are how to handle this situation in the future as it seems likely that its going to happen again and I'm confused about what this dog is doing anyway.
Although this dog does seem very aggressive, it hasn't actually bitten either of my two dogs, it just growls and snarls and gets on top of them, and it seems its trying to bowl them over with its body weight, so I wonder if I'm over reacting or mis-interpreting what it's doing, although I have to say I do find it quite scary when this dog runs up to us with its tail in the air growling and snarling, showing its teeth. But then again, it did seem to be wagging its tail at us on this second occasion, even though I had just kicked it under the chin, unless it was wagging its tail at its owners approach?

As for the future, I guess I could just about manage to pick my two dogs up, as they are both smallish too? I don't want to kick this dog again really as I know it's down to it's owners and not it's fault, and I don't want to turn it people aggressive too, if it is already dog aggressive.
I guess I'm just confused generally with how to handle things and would be grateful for any tips please.