What happens after the ME3 credits roll?

I found this quote at Attack of the Gameboy which refers what happens to your ‘game’ once you have completed Mass Effect 3. Can you go back and finish off quests and the like, or is that it? Here’s an answer of sorts:

"It's probably going to be a combination of [the first two games]," executive producer Casey Hudson said. "We're going to have a version of the post-game state that you can go back to and finish more stuff, but then we'll have stuff you can loop back around and do in new game. It's a hybrid of the two."
So what does this mean? Well, if you do some deductive reasoning – it would appear the Reapers do not manage to destroy all sentient life in the universe – cos if they did there would be no body to talk to in game post credits right?

Extra for Experts: Why the Male Sheppard is only used in ME3 Marketing