Dressing Like Adolf Hitler?

I have been invited to a birthday party which is fancy dress, all the people going are slightly mad etc, somebody is going as a terrorist and another as a Nazi fighter etc. When I heard this I thought it was be good to go a Hitler and join up with the fellow Nazi. The party is in a private house so nobody will be offended, I was just wondering how to dress like him and what colour and style coat and shirt i need or if there is a pre-made costume on a website? Many thanks.