hi!That �s exactly the case with one of my students.
I don �t think you can use any coursebook with her, as books that cover the vocabulary you need will probably be far behind her in terms of grammar and structure.
What I do is identify the vocabulary areas we need to work on, then choose a number of words that I believe she can master at this stage and prepare worksheets for her. Sometimes I write a short text of my own with all the new words I want to teach her. Sometimes I just use pictures to match. Then I give her plenty of exrcises to put the new words in use, crosswords, fill the gaps, match words and definitions, use 2 random words together in a sentence, anything you can think of that will work with your student. I also try to make games with them, boardgames and role-plays where she �ll have to use the new vocabulary. Revision every 2-3 lessons is essential, too.
It �s always best to introduce only a few new words at a time. Also to include words that you know that she already knows, to boost her confidence. As homework you can ask her to choose those words that she finds more interesting or useful and write something with them. It can be isolated sentences or a short dialogue (more demanding).
There are plenty of vocabulary oriented worksheets here at eslp that you can use, too.
A graded reader will help her with reading and writing, but I don �t think you can fill the gaps with it alone.
HTH!