Working With a Scared Abused Dog?

Hippa (my Staffy) was found under a freeway with a broken leg and scars. She had obviously had multiple litters. Her microchip took us to the original breeder and as far as I can tell she was a show dog that went to a family where she was stolen, brought to the city, had her ears cut off and used as a puppy mill.

I am an alpha to dogs and have dealt with problems before. This dog is a princess. But, when someone aggressively walked behind us with leashed aggressive dogs, she made eye contact with me which is her training for stressed situation. I couldn't get off the path and the poor dear actually began shaking and leaning on me. My heart broke. She has not left my side since. Yes I have acted normally with her since and I gave her some tasks to do for routine.
My question is...Is there any way to help her come back to the present when the trauma is that bad? I now know she was attacked and probably used for baiting. She actually likes other dogs and people. I have had her evaluated by the trainers that work with possibly aggressive dogs and she aced every trial.
What is the best way to help her after a situation like that? And other than sit, focus on me and ignore the scary stuff, can I do more?

By Shasoren from Richmond, CA