Given how many people are searching YouTube for A Game of Thrones previews for the HBO show a great way to help advertise BoW's might be to put together one of those intro videos that FFG's puts out for many of it's other games showing off the game and giving a basic overview.
Of course the video would be cleverly entitled: A Game of Thrones: Battles of Westeros and the video description would link straight to the BoW's front page.
If it can be done for many niche games then there's no reason it can't be done for something with a major TV show tie-in. I'm sorta surprised there isn't already one.