Sorry for the lack of news on my end, Monsuno Fans. Been... neglecting a number of things, so I haven't been able to really do much of anything. I'll try and keep you guys up to date.
First off, some good news. Season 3 of Monsuno has entered into production. As of June 2013, Episode 58 (or Season 3, Episode 6) has been worked on by Studio Wanpack, a studio that does outsource work on the show for Studio Hibari / Larx Entertainment. I'm not entirely certain when the third season went into production, but it is good news for people wondering if we will get more episodes past Episode 52.
Second, according to Fremantle Kids, there the new season will be 13 episodes long. No name given for it yet, though Japan will still apparently be using the "Juusen Battle Monsuno" name, from the Wanpack page.
Also, as of this posting, Japan has aired up to Episode 40, with 41 airing next week.