Assuming this is a letter head, you'll want to format it like so:
Holly Medical Center 55 E Panlin Circle Atlanta, GA 30320
Dear Dr. Remo,
you place a comma between a city and a state (Atlanta, GA) and you leave the zip code with the city and state. with the address (Dear Dr. Remo), you must place a comma after it to show that it isn't a full sentence and you plan to continue with your letter.