40 grams of protein after a workout is standard.
You have to realize that not all of it will get into your system.
Some of it gets broken down and elimated.
You want to make sure your muscles have all the amino acids they need at this critical time. So it's better to have too much (within reason), then it is to have to little.
I definately would take at least 30 grams post exercise. This will also help you reach your goal of 1 gram of protein/1 pound of body weight per day.