Actually, I would hesitate to use a citronella collar in this case. In fact, I would highly discourage it. The citronella collar's purpose is to punish the dog for barking. In this case, this is bad for two reasons: 1) By punishing the barking, you're only suppressing the symptoms. To fix aggressive tendencies, you need to fix the cause of the problem, not the symptoms. 2) By punishing the barking, you're punishing all warnings of an attack. Barking and growling are normal dog warnings. Warnings are GOOD; they tell us, "Hey! Something isn't right; I need to back off/change something/whatever". If you punish the warning, the dog can eventually learn to skip growling/biting and go straight for biting. I've seen this many times, and it's disturbing and unnecessary. Dogs who do not warn before they bite are infinitely more dangerous than dog who DO growl and bark before they bite.

In the past she has just ignored me and again tried to get around me when I block her.
Of course! All dog reactive/aggressive dogs would rather look at the trigger than focus on you. That's what the "Look at That" game is for. It's to teach the dog that she CAN look at the trigger. In fact, the trigger becomes a game to play with Mom. Thus, the dog can look at the trigger and focus on Mom at the same time. Novel idea, eh?

I would love to make a game out of this. Maybe I could say "Dog" when she spots it then give her a treat? She stares at the dog for a bit before she starts barking. She only bark when the dog comes closer or starts going away.
Yes! Saying "Dog" right when she spots it and then treating her is EXACTLY what I recommend I would actually do something like "Dog!">click>treat. Repeat. However, don't let her stare. She can glance at the dog and use it as a game to play with you, but, if she's staring, that means she's over her threshold and she needs to move farther away from the dog. Hope that helps you!