You have certainly improved her appearance/condition in the time you've had her...good for you!
I am with Nathan; I would not give banamine more than once a day, unless in EXCEPTIONAL circumstances and on the INSISTENCE of a knowledgeable equine vet(for the reason Nathan cited, as well the ulcer risk.)
May I respectfully suggest you find a halter for her that fits well? I just shudder w/ dread when I see such a loose-fitting one on ANY horse; there is a real risk of getting 'hung up' either by a foot through the halter OR the halter hung on any projection- VERY dangerous, as the halter will NOT break.If she is gentle, there should be no need to leave a halter on her; ;you can put it on when you need to handle her, then remove it when you will not be right there working w/ her. (I personally never 'leave 'a halter on a horse, unless I will be right close by at all times...and even then, almost never.
She seems to be doing well; you seem to be handling the situation as required. Best wishes for a quick and uncomplicated recovery for your little Cupcake!
Margo