From what you said, the guy seemed very concerned about what his dog did toy your puppy and I really don't see a need to call animal control. If he refuses to have anything to do with the problem get them involved, definatley. If it happens a second time with the same dog I think maybe you'll need to call them then.

No, you shouldn't expect attacks like this in the future. It could have been the prey drive or the dog could have been "Dog aggressive". This means they hate other dogs and will attack them if the had the chance to. Maybe that is what the Rottieweiler is. I have a Maltese(who you can see in my avatar.) and she is always the one trying to attack other dogs. But the point is DO NOT expect other attacks to happen.

I'm so sorry to hear about your poor puppy. She must have been terrified! I hope her wounds heal okay.