Usually if a anime series ends very differently compared to the story in the manga, they are not going to make a sequel to it. Most if not all the info about a sequel in the works are just rumors.
If they do actually make a sequel, there isn't enough material in the manga currently to make another series. The most they can probably make right now is a 13 ep. series at best.
It is a great series if you don't count the ending. Even though I watched the whole anime series and read the manga to the most current issue, I still bought it on blu-ray and all the manga that is out because that is how much I like the series. Watching or reading it on the PC, doesn't do the series justice quality wise.