Here's the cover for the aforementioned novel (simple, lacking the official logo, and a bit covered by the text at the bottom, but fitting).
The contents include the sequel story which involves all 13 riders (Earth to Ventaran ratio isn't specified but all the decks/powers will be used), papercraft Advent Decks and Cards, various interviews (discussion about the remake, quality of the show, the 2009 "Rider Boom," praise from Japan audiences, the emmy, etc. Also apparently they regard the show as "four seasons long.")
The novel itself is written by Mano Katsunari, who recently wrote the Drama, Shinzanmono.