Should you take whey protein before and after your workout?

No, not needed both times. It is better to take whey protein after the workout. After a workout is when your muscles would need protein to repair and grow. So providing a whey protein shake within half an hour of workout helps.

Prior to the workout have a good high calorie diet. This would give you strength to workout properly. Include bananas, glucose and milk in your pre-workout diet to have sufficient calories for the workout.