I highly doubt they will be releasing -any- Marukaite chikyuus anymore. If she gets -any- song, it'd more than likely be Hatafutte Parade. It'd be a while from now, though, because they have to release ones for all the main characters still...
(Edit: Sorry, forgot to log in first)
On September 21st, with vol. 8 of World Series on DVD, Hungary will be getting a Hatafutte Parade alongside Prussia. Their previews have been released recently.