Chloe's a hero! So glad she wasn't injuried and hope her puggie friend is okay too. Good for you for being proactive....sorry I'd hit, kick, throw whatever was handy too.
Our dog park doesn't even have a seperate little dog side...there are always big dogs there so I don't take Ramsey or Reese. I'd say at least that pitt should be banned from the park.
My neighbor's yorkie was in her backyard and the two rotties from next door dug under the fence and killed her.
I don't think you can defend any dog that takes blantent actions such as jumping or digging under a fence to attack another dog....