I am sorry to say that there is still no new stand-alone installer on GOG. It is still version 1.0. I have contacted consumer support on GOG, and they said they will contact you about the situation. I really don't want to complain here, but I am starting to loose hope I will ever play this DLC. I am not sure who is responsible for this situation any longer, but it seems it's getting nowhere.
I really hope this will be resolved at some time, but I guess it won't be soon.