OMG. When I first read your posting, you said, "a...German Shepherd attacked my 7 month old..." My first thought was a GSD attacked your 7 month old baby, not puppy.
Anyway, my previous dog was attacked by a big white pit bull mix at a dog park. (Up until that incident, he was friendly to all dogs. Never went to a dog park after that.) From then on, he would aggressively bark at every big white dog in my neighborhood (there were 4 big white poodles that lived in the neighborhood) that crossed his path regularly. He wanted to tear them apart. Even in his last 2 months - fragile with a broken leg, loss of weight, feeling sick from vomiting, and dying of liver cancer - big white dogs would still get a rise out of him. I used to take him to the annual pet expo around me, and after that incident I couldn't anymore. What I probably should've done was hire a good trainer after and worked on it. Woulda, coulda, shoulda.