Excellent discussion of potassium metabolism and management can be found in:

http://www.hmc.psu.edu/healthinfo/h/hypokalemia.htm

Potassium Metabolism and Dosing:

Potassium replacement must be done in accordance with clinical findings (muscle weakness and cardiac rhythm abnormalities) taking precedence over numerical value of serum potassium.

In normal people:
A decrease from 4.0 to 3.0 mEq can correspond to 200-400mEq potassium deficit.
A decrease from 3.0 to 2.0 mEq can correspond to 200-400mEq potassium deficit.
Decreases below 2.0mEq can represent a deficit larger than 800mEq as intracellular potassium begins to compensate.

In periodic paralysis, these deficits may or may not hold true. The hypokalemia in hypokalemic periodic paralysis is due to POTASSIUM SHIFTS rather than deficit. Therefore, more conservative potassium replacement is needed.

Potassium Content of Foods:  http://www.nal.usda.gov/fnic/foodcomp/Data/SR16/wtrank/sr16w306.pdf

Another good source about nutrient content in foods:  http://www.nal.usda.gov/fnic/foodcomp/search/