Did your visual disturbances stop once the Topamax left your system? Also how many times do you think you take Midrin or Tylenol each week and at what dose? You've probably been told this before but using analgesic medications more than a few times a week can perpetuate your headaches or even transform episode headaches to chronic ones.
Have you tried any neuroleptic medications as abortives? Also, what about the more common triptans (Imitrex, Maxalt, Relpax, etc) or DHE?
And what about interventional treatments? Any outpatient infusions or planned hospitalizations for IV DHE or Lidocaine? Have you had nerve blocks or trigger point injections? Or Botox treatment? Any alternative treatments like biofeedback, acupuncture, physical therapy, chiropractice, etc? Have your tried any psychological treatment (medication or therapy based)? I don't ask this to imply that you have any sort of psychological problem but because psychological treatment often compliments other headache treatments.
Also have you been able to isolate any major headache triggers? Keeping a headache diary or log can help with this. Additionally, making dietary changes can help you find whether any foods might affect your headaches.
Sorry to ask so many questions but I really need a better idea of your situation to give good advice. From what you posted it sounds like you've had a rough time and have tried a lot, though it also sounds like there are a lot of things that you haven't tried. Let's see if we can help you!
DX: NDPH, Recovered(?) CRPS
RX: Lamictal, Concerta (Methylphenidate), Clonazepam, Wellbutrin XL, Namenda, Rozerem, Magnesium (1000 mg/d), Riboflavin (400 mg/d).
PRN: Ketamine nasal spray, Oxycodone, Toradol, Celebrex, Haloperidol, Lodine, Migranal, Zofran, Phenergan, Thorazine, DHE IM, Droperidol IM, Reglan, Ambien CR, Provigil, all triptans