It sounds like you need some potassium, magnesium and some calcium.

You can get something called NOSALT which contains 650 mg of potassium per 1/4 teaspoon. You can either sprinkle it on your food in place of salt
or put a 1/4 teaspoon in a glass of water and drink it down. I found drinking it down the easiest to do.

Also get a calcium supplement with magnesium in it and take that along with your multivitamin and that should help get rid of the leg and foot cramps.