Do you have a car?
I'd just poo/pee my dog in the yard.
And every other day (or so) pack up my pup to go somewhere safe for a nice long walk. That way there is no stress for my dog or for me.
I'd also start being EXTREMELY proactive with meeting FRIENDLY dogs that are off leash so your dog will get it's life back to normal. I meet off leash dogs all the time and we do NOT get attacked. Most of the time they are just coming over to be happy and friendly and much of the time they are puppies. I'm like you that I do NOT want my dog to attack and injure a puppy that just got out and is running up to say hey.
So as important as it is to assure you don't meet any 'bad' dogs and have a real fight. I'd be making sure I meet tons of 'good' dogs so my pup starts learning that in the real world most dogs are ok so they can relax and enjoy the world and meeting the dogs in it.