The toxic dose for aspirin that I have seen cited most commonly is 30 mg/lb up to 40 mg/lb, which would be 20 -26 tabs for your dog. The pills she ate were absorbed within the first hour at most.The half life is about 8 hours, which means that half the original dose is metabolized and excreted within 8 hours.The aspirin was absorbed within the first couple hours.
Toxic effects include depression, vomiting, increased body temperature,electrolyte imbalances, coma and death. Gastrointestinal ulcers and decreased clotting are other common side effects.
You can wait and watch on your own. You could give Prilosec to help prevent ulcers.
If she ate every one of those pills; however, she got 54 mg/lb, well into the toxic range. You might get away with wait and watch. There is no specific antidote, but the best treatment would be IV fluids, drugs to protect her GI system, monitoring electrolyte levels, etc. Your best bet would be to go back to the emergency clinic.
The best info on toxicity and treatment is from the National Animal Poison Control Center(NNN) NNN-NNNN The current fee listed on their web site is $60. YOu can call, but let the vets do it if you go back. that saves relaying info or paying twice.
I hope everything goes well.