As a base-line you should have protein + carbs after the workout latest whitin one hour (closer the work out, the better, say in 20-45 mins.).
For muscle growth/rebuild there is a "window of opportunity" which is gone after 1 hour. There are studies made on this.
To my understanding (sorry.. no reference..) easier the workout (intensity & duration) less protein and more carbs (e.g. 1-4 ratio), harder the workout (e.g. have weight training) more protein (1-1, 1-2 ratio). Usually fast carbs & low fat (after workout) are recommened in order to get incredients quickly (whitin the time window) to your circulation.