This link provides helpful information about food sources of potassium
Potassium | Linus Pauling Institute | Oregon State University.
I meet the potassium RDA from the fresh fruit and vegetables that I eat.
Medication for hypertension is complicated, Current evidence suggests that beta-blockers are not recommended as first line treatment
Beta-blockers for hypertension | Cochrane. Others may be better - I am on a calcium channel-blocker which works well for me.
Life-style choices, in my case regular exercise and stopping drinking and smoking, have also helped me.