Is this the song you are looking for? Try searching for the name of the anime instead of the artist https://www.youtube.com/watch?v=wzTkbGzPOow
I haven't ever downloaded from this website but I found this http://downloads.khinsider.com/game-soundtracks/album/kono-minikuku-mo-utsukushii-sekai-original-soundtrack-1
Found it on American Amazon didn't find it on Itunes Japan http://www.amazon.com/This-Ugly-Yet-Beautiful-World/dp/B000H5V8S6