Welcome! I'm sorry I can't help with the IEP part, but as far as the reading level goes. My DD6 is also about the same level. We got the librarian on board with helping her pick appropriate books. While she was allowed to choose a book or two from what ever level, she was also nudged (read that as made to, in a kind way) take out books at her level that were of appropriate topics.
DD's math is also weaker than her verbal. Same as yours, it is still above grade level, but it is almost 2 yrs below the reading level. For our DD, I think it is all about how math has been taught to her so far. It is not done in an interesting or creative way, it is just boring sheet upon sheet of the same thing, and then a timed test to see if they can do the math quickly or not. DD is not into that sort of thing at all. If they would make it more enjoyable, I think her level would rise quickly.
So,you're not alone with the variety of levels in your daughter. Others will be able to answer more questions about IEPs though.
Again, welcome!