Well adding water pills would work but I think the better choice it to eliminate the cause. Ask your doctor for a different class of drugs. Maybe water pills INSTEAD of the channel blockers.
Diuretics work pretty well with ARB's like avapro. Perhaps a very small dose of thiazide might avoid the dry mouth, but if you are getting paresthesia from the water pills your doctor will have to get creative?
Beta blockers and ARB's aren't a great combination, but perhaps worth a shot?
Can you get CLOSE to enough control with the Avapro alone?
Then there's the CHANCE that one of the other channel blockers (amlodipine, nifedipine) might not cause edema.
(I think living with edema is out of the question.)