Most fast food restaurants will give you the nutrition info on their food if you ask. If all else fails you could find the calorie info and figure how many ounces were in your drink.
According to CalorieKing.com Coke Classic 32 oz is 419 calories or 8 points. If it was 48 oz then it would be like 629 calories. Sorry my points slide doesn't go up that high. Would be over 12 points.