First off: Great, great movie. It's the best non-anime animated movie that no one's heard of in the U.S. Not as good as How To Train Your Dragon, but definitely shouldn't be missed and should have been more popular.
With that said: I it looks like your link is the DVD version, I saw that bundle at Wal-mart; the Blu-ray released much later without the comic for about the same price:
DD is having a sale on some kids shows/movies now and you can get this same DVD set with the comic for about $6 with the code KID50. It's currently OOS so it's no gurantee to ship: