It sounds like it's time to try a medication other than the traditional stimulants. Your options are:

-Intuniv: A blood pressure medication that has been found to help in a small portion of patients with ADD. It stimulates alpha adrenergic receptors in the prefrontal cortex which is thought to help improve inattention.

-Wellbutrin: An antidepressant that inhibits neuronal uptake of norepinephrine and dopamine uptake. It is more energizing than most other antidepressants, so may be "stimulating" for ADD but the exact mechanism for its effect is uncertain (as with many other psychotropic meds!)

-Strattera: strictly indicated for ADD use (for now). Norepinephrine reuptake inhibitor.

best of luck to you! keep us up to date on what your doctor and you decide to do next.