My son had terrible astma when he was a baby, and I remember how hard it was to be patient with him, when I had been up with him most of the night, (night after night), and was so sleep-deprived that I could barely function myself!
So advice from me is to make sure you get as much rest and support as you can possibly get in this period. This child needs a well-functioning adult around her. She needs boundaries around her, and for you to be consistent. She needs to feel safe. Part of what will make her feel safe is to experience that you are predictable. But pick your battles. In the beginning , I think you should stick to a few things and be as consistent as possible about the rules regarding that. It is better to be consistent about a few things, than not to be consistent at all. As a parent, I have found this to be helpful advice. To be absolutely consistent about everything in her life is impossible, and it is only going to cause a lot of stress and feelings of failure in yourself. And keep timeouts not too long. If she is five, then five minutes, if she is ten, then ten minutes, etc. We had to resort to using time-out for my son for a while when he was younger, and found it to be helpful. Some times I remember I was so upset with him, and I found that it was better to do a time-out - he got the message, and I got a few minutes to collect myself!
And P.S. Bedtime is important. Dont let anyone tell you anything else. Try to get her on a bed-time rutine. SUPER-IMPORTANT! We neglected this with our son, and it has just caused a lot of problems that could have been avoided. He struggles to this day with going to sleep, and I suspect it is because we were too lax about that. I think what you are doing is a great thing, and truly wish you success in helpng this child to get through her (no doubt ) horrible experiences.