Brandie,
If the main problem seems to be not enough review (which I know Singapore is weak in that area), then I don’t know that Saxon would be any better. It’s a spiral program, not a mastery based one; so she won’t “master” a concept before moving on to the next one. For some children that works-those that are naturally math-inclined; however, it’s not so good for others who aren’t so inclined.
I suggest Math Mammoth; the instructions are very clear and it, thoroughly covers a topic before moving on in a style that is very colorful, allowing for an artistic or a visual type learner. It promotes independant learning, too. I know Saxon can be very textbookish and CMer’s, as a whole, don’t find it to be a very good fit.
MM is also very reasonable, price-wise. It goes to 6th, with Pre-alg and Alg. in process.
Sorry, I know I didn’t really answer your question; but I thought it important for you to have that info. about spiral v/s mastery before you spend the money.
Rachel