Does O have the ability to chart or track her focus and how she feels? If she had a watch beep (or vibrate) every 20 min, could she put a smile, meh, or frown on a chart? Helping her become self reflective as well as getting data on how she's doing, might help you make decisions.
If your school doesn't feel like an IEP is called for, ask for a 504 plan. It is similar to an IEP but the kid does not need to hit the same threshold of how "disabled" they are to get one.
Is she easily distracted by things going on around her? Would moving her seat within the classroom change her level of focus. When she does homework at home, what is the environment like? If she moved environments, would that help? Would she do better with other learning modalities-- audio books, thinking aloud, drawing answers before writing them, etc?
Have you observed in her class? What do you see in her behavior (yes, it will change by your being in the room, but it sill would be some data).
Kids her age are not my specialty, but I'm happy to help you think things through.
This website might be helpful: http://www.ldonline.org/