Adhd??? rx -vs- holistic -vs- dietary changes??? i am lost?

my child has been diagnosed with preschool adhd (by a prefoessional, which took 3 monthes of weekly 50 minute visits). she is nearly 4 and unbearable most days. i am lost at where to go from here. most rx drugs are not tested on children under 6, yet the websites for the holistic treatments seem cheesy like a bad sunday morning infommercial. Some say a gluetin free diet works. What has worked and what is a waste of time??????