I just go to my local BMW dealer and pick up their filter kit. I was at advanced auto parts the other day, and they now carry the filter/gaskets etc.. in a box, but about 1 dollar less than the dealer.
Then just get 7 quarts of either the BMW oil (Castol 5W-30), or Mobil 1 0W-40 European synthetic. Good luck!
-Joe
My 135i Site