Good for you!!! Thank you for helping!
As far as the diarrhea, I know she is skinny, but the diarrhea won't help her gain at all. After the worming treatment, you may try fasting her for a day, then feed nothing but over boiled rice until her stool firms up, then add boiled chicken slowly to the rice. As her stools (meaning her gut) gets better, you can gradually introduce her standard food. The diarrhea is caused but the inflammation of her gut that the parasites have caused. Until the inflammation is treated, she will continue with the diarrhea. I know you want to pour food into her and help her gain weight. The best way is to treat the problem, cure the inflammation, then fatten her up. It takes a while and it will grate on your nerves to have to move slowly, but trust me, this is the fastest way to help her. Even once the parasites are gone, if the inflammation isn't treated, the diarrhea and the weight issue will not get better.
I wish you the best and thank you again!