You must definitely get yourself a copy of Beyond O.K.! I'm sure you will find it very valuable! Lots and lots of amazing and eye opening stuff not found in The Einstein Factor, or many other places for that matter.
Discovering The Obvious has also gotten some terrific reviews, I'll probably get myself that one too some day.
Buy the Einstein Factor, I'm not completely sure you need to spend the cash on the tape-set, though, the book itself probably contains all of the tape course, even more. Richard Poe's writing style really helps too, he's definitely much better with words than Wenger, compare The Einstein Factor with Beyond O.K. for proof of that. I read the Einstein Factor in a single night, and I don't often read books in a single sitting like that. Interestingly, I also did that with another book written by Richard Poe. While Poe probably hasn't contributed much of the material in the Einstein Factor, I feel he was the one with the typewriter when they did this one.