Update on my dog. (sorry for all the posts in a row)
Took her to the vets again yesterday early morning. It seemed she was getting worse. Got a doctor who is apparently one of the owners of the clinic. He recommended putting her on IV fluid drip for 24 hours so left her in the care of the doctor and hospital. Called him today and he thinks she is getting better. He recommended getting her and bringing her home at this point and she's back, resting.
He thinks she has HGE (Hemorrhagic gastroenteritis). He said it has nothing to do with the chocolate or anything else she might have ate. He recommended moderate amounts of water and giving her the prescription or even her regular dog food. Asked the doctor about what dog food we should give her. He said Purina Pro Plan is good. I mentioned the Beneful thing to him and he told me that while it is cheaper, it isn't really all that bad and it's okay to give it to her but said if we want premium dog good, go the Pro Plan route.
So right now we'll just keep her under observation 24 hours a day as we've been doing. She seems a little bit better in that she can walk a bit more and her head movements okay. She was eating and drinking at the hospital which is good too.
Edit: Looked up HGE on Wikipedia and it sounds pretty much right what she has. According to the article, it starts with vomiting and then goes to bloody diarrhea which is what happened with her. The article also says treatment is usually intravenous fluid therapy which is what she just got.