I would recommend a test-prep book on the GED, which you can buy in any bookstore. I have co-authored a book called Keys to College Studying that would also help her to build her reading, writing, test-taking, and critical-thinking skills. After she has worked through a couple of books, she should be in a much better position to pass the test. You may even want to have her take an additional reading course at the local library or for no credit at your local community college.