http://www.autostadt.de/Is the place to go you get a free vw factory tour with your ticket entrance but book up asap if you want an English speaking tour
you can also book other things like
the car tower and off roading experience
the food is fantastic loads of pukka restaurants on site I can recommend the beef club
but you must try the vw curry wurst sasuage and original source
its big enough to spend the whole day here if you do the tours
the museum
http://automuseum.volkswagen.de/events.htmlis ok some some famous cars but after 3 hours I was ready to leave tbh as I am a water cooled guy and it is half and half air/water about 80 cars max I would say
and the vapiano Italian self service restaurant
http://de.vapiano.com/en/restaurants/vapiano-wolfsburg-porschestrasse-26-30/is a great restaurant we didn't think that it was expensive but very busy well worth checking out
all are within walking distance but the museum is behind the stadium so if you are at the Autostadt then expect a 30 min walk 5 mins I a car