The first step is that she absolutely must know her addition and subtraction facts fluently without counting on her fingers. You need to have her work for 15 minutes a day at least 5 or 6 times a week on addition/subtraction drills. Online programs never worked for my kid. I had him do a front and back page of this book:
http://www.amazon.com/Plus-Methods-Learn-Addition-Subtraction/dp/0977732304
There are around 230 pages. Have her do 2 pages (so one page front and back) and do two to three minutes of flashcards one the problems she has learned so far. In 115 days or 4 months if you do it everyday you will see a big improvement. It used to be that math facts were emphasized in schools. They aren't at most schools. My older son really needed the written, daily practice to memorize math facts. Once he did he took off in math. I looked at research that once you memorize math facts it frees up working memory to allow you to concentrate on harder problems. My younger son didn't need as much practice and just seemed to pick up the math facts without much practice. I don't think it has anything to do with intelligence.