Personally, I would push the school. I know that not every child reads early or easily-even gifted kids-but it just seems unusual that a child who has a high Verbal score would be struggling to the point of the school performing an IQ test. You know your child best, and if you sense something wrong, it probably is.
I have a son who is in 6th grade - he's extremely bright. We haven't had him IQ tested, but he is in gifted, and just took the SAT and rocked it. He has an IEP for speech and for expressive language. So, your school is insane to suggest that a student with a high IQ can't have a learning disability. You might want to post this on the 2E board (If I knew how to make this appear there, I would). My son's difficulties didn't show up on the regular tests and even the speech path didn't realize that it was a problem until I talked to her and she then did very specific testing.
They must at least respond if you put a request in writing. I would make it clear that you feel that she has a learning disability and you are requesting a complete evaluation for an IEP.
She is moving from the "learning to read" stage to the "reading to learn" once she gets into 3rd and 4th grade. Good literacy skills are essential.
BTW, I don't think that the gap is a big deal, so I do agree with the school on that, but don't let the reading thing go....
Good luck!