Where can I get the sheet music for the song Crescent Moon Dance? I hope this is not too off-topic, but I recently watched Hibike! Euphonium (Sound! Euphonium), and I was wondering if anybody knows where I can find sheet music for the piece that they play in the competition. Specifically, I'm looking for Crescent Moon Dance by Namie Horikawa (I don't know if this is an alias or not). I play the trumpet, and I really wanted to try out Kousaka's solo. If anybody could help me out, that would be appreciated!
According to the official website, the official sheet music for Crescent Moon Dance 「三日月の舞」 was given as extra on purchase of the Volume 1 of BD/DVD at certain stores in Japan1. Unfortunately, Volume 1 already went on sale on Jun 17, 2015.

Likewise, the sheet music for the opening 「DREAM SOLISTER」 and the ending 「Tutti」 will be given as extra on purchase of BD/DVD Volume 2 and 3 respectively.

1 The stores as listed on official website: 玉光堂、バンダレコード・ライオン堂、ＪＥＵＧＩＡ、十字屋CROSS、新星堂、山野楽器、ヤマハミュージックリテイリング

The advertisement, as posted by one of the stores on Twitter, inviting people to reserve a copy of the BD/DVD for the sheet music: