Hi again Vowel Lady, yes it is often difficult to get all the potassium you need while on a diet.
The product I use is called Revive fruit punch from Vitamin Water Zero. Most vitamin waters contain very little potassium, but this one has 880 mg of potassium per 20 ounce bottle. The best part is there is no sodium or sugar in it, and it contains the natural sweetener Stevia instead of an artificial sweetener.
I also drink low salt V8, which has 1180 mg of potassium per 11.5 ounce can. So, if you were to drink one fruit punch and one V8 per day, you would be getting 2060 mg of potassium just from those two sources alone.