Diablo III expansion on ps3?

Is Reaper of Souls going to be released on PS3 just as an expansion like on PC? The only Reaper of Souls I see for consoles is the Ultimate Evil edition. So if I i was to just buy the base Diablo III for PS3 could I still get the expansion some how?

Lucky the ultimate Evil version is also going to be released on the PS3 along with the PS4 version. But there doesn't seem to be a DLC add on for the PS3 game. Which would be nice. But looks like you just have to get the "new" game.

Just a little off topic but are there a lot of people online on the playstation 3/4 versions?