The standard answer would be to consume a large liquid meal of which the calories consist of 60% high-glycemic carbohydrates (buy maltodextrin, dextrose, or both), 40% whey protein isolate, and as close to 0% fat as possible. You could mix 60g maltodextrin with 40g whey protein isolate and drink that immediately after your workout. Don't use fruit, ice-cream, lactose, milk protein, fiber, etc. as these will not help you. They will either slow absorption or replenish liver glycogen stores before muscle glycogen stores (in the case of fruit --- fructose).
A drink will be more immediately effective than solid food. If you are in a situation where you need to eat at a restaurant or something after a workout, I recommend getting a low-fat sandwhich on white bread w/o cheese at Subway. It has high GI carbs (white bread) and protein with little fat. Get it?