OK... some comments from someone that used to teach this stuff to medical students. Me.

[but, as a disclaimer, I'm
not a physician]
I think the wrist-cuff method is inferior to the standard sphygmomanometer. The wrist method typically uses a algorithm to calculate BP (and actually utilizes a more indirect method involving plethysmography). Even an electronic sphyg (that compresses your upper arm and gives a digital read-out) is better than a wrist unit. Compressing the brachial artery and listening for Korotkoff sounds is the industry standard... and is easy to learn with a stethoscope.
Anyway, differences between arms is not unusual (especially if less than 15mmHg), but there are conditions that can cause a serious difference (such as a "carotid steal syndrome"). I'd make sure your doctor isn't concerned about it.
As for meds, it is not unusual at all to require several anti-hypertensive agents to get it into line (sometimes peripheral vaso-dilators, sometimes cardiac inhibitors, sometimes blood volume lowering drugs, or, very often, 2 or more of those). Don't be surprised if you're told to take Attenolol, Vasotec, Avapro and/or Enalipril, etc. and don't fool with the dosages.
Your diastolic is high... way too high (if you ask me - especially if you're already on meds for it), and more concerning. So:
1) measure your BP using a different method (and I'd junk the wrist unit) - go to Target or a drug-store that offers it
2) see your doctor ASAP.
Hypertension really is a silent killer and should be taken seriously. You won't feel bad while end-organ damage is happening.
[EDIT: I hope I'm not too alarming. Your BP values from a wrist unit might be falsely high. Get a reliable reading when you are at rest, and see your doc in January or earlier if you can.]