Other merchandise currently includes:
The Original Novel
This hardly counts as merchandise - it's the source material, after all!
I don't know whether the novel has been translated into any languages other than possibly Chinese judging by posts elsewhere in the forum (maybe that's a fan translation?). The novel itself is now most readily available in three volumes priced at around 760 yen ($9.50) each.
If you click the links under each volume on the show's official website
here it'll take you to the Amazon Japan pages to buy each of them. I'm sure the novel is available at all good Japanese bookshops, but from the looks of things the covers are being reprinted to feature the anime characters so who knows?
The Manga
The first volume of the manga was released on October 9th. You can buy it from Amazon Japan
here if you so wish.
I think that's it for merchandise at the moment - the show's website doesn't even have its merchandise section up and running yet, so who knows. We can hope for some kind of artbook given the quality of the art in the show thus far, but who knows?