Thank you for your answer, Fluke.
I will begin a new game to be sure to enjoy every new assets and be ready for the release of the full game. In that way, I'll be sure to access to the new areas et quests. I think that this part of the game is quite finished now, so it's safe, I hope, the begin a new game now and keep playing from it in Marsh, when the full game will be release.
Thank's again !