It sounds like you're already doing a great job. I think programs may bog you down too much and perhaps be discouraging. Your daughter wants to write, so ...
I would also suggest Brave Writer. It treats students like would-be writers. You can buy The Writer's Jungle at Homeschool Buyers Coop for a 50% discount. I haven't finished reading it, but think it will help you know the stages your child will go through, and how to support her.
There's a story in there (or online, I read too much so can't be sure where I saw it) of a mother saying her struggling older child went through all the phases in less than a year, went from being virtually a non writer to a confident writer. If you wish to you can then contact the author Julie Bogart and ask her advice about other resources you may like to use.
Hope that helps!
Would love to hear what works for you.