I have seen worse, but ...
I have seen worse, but not on a bimmer!! Holy cow. Fortunately, it looks to be jsut dust and dirt. Will come clean easy and will look like you are a magician. I use very diluted whote lightning from 4 star for the dash areas, a stronger version for the capreting, and a mid-to-strong leather cleaner, should be able to use what you have there. Good luck, though you might not need it, dirt is easy, swirls on the other hand ... uugghh!
Now once clean, use a good quality protectant or dressing to give the like new look, I am a fan of the 303 line and would use that, but buff when dry for that matte look.
-Matt