My nephew-in-law had ADHD and he took meds during the week. Then his imbacile of a father took him off the meds for the weekend and that poor boy would literally bounce off the walls. What a roller coaster.
The message here is to find the proper dosage and stay consistent. I have read quite a bit about the relationship with foods (removing sugars and chemicals in processed foods) and the severity of ADHD. It's worth a try.
In addition to the meds, it is important to find out what motivates your daughter (and use that effectively) and to develop a routine for her. ADHD children tend to do better in a routine because their internal life is so hectic. I think it is important to break instructions down and dole them out in smaller doses. Where most people can retain and act on a list of instructions, ADHD sufferers can get sidetracked by too many details.
Good luck with your DD. She is a lucky girl coz her Mom loves her and wants what's best.