Just found on ticketmaster that they are selling parking tickets for park and walk sites quite close to the stadium.
Given that there is a 2km car exclusion zone around the Ricoh this might be the best way of getting as close as you can in a car.
Both park and walk sites look quite close, about 10-15 min walk away.
http://www.ticketmaster.co.uk/event/...1&minorcatid=1