They updated the image on the main home page:
http://www.nagisama-fc.com/anime/index.html
Don't know if they gave an air date yet though, doesn't look like it (although since my Japanese skills are next to zero, I'm not sure I could tell if they did...).
Character pages have updated images, like the character designs so far...especially after reading the manga that's been scanlated so far, definitely looking forward to this.