I pre-ordered the witcher 3 here on gog and I can only see avaliable part one of Reasons Of State.

Where's the house of glass comic or the rest of ROS?

The store page indicates that I should be able to get for free the three comics already(house of glass and part one and two of ROS).

EDIT
my bad, I got the purchase email late and it has a code for house of glass. Still wondering where ROS part 2 is thou.

There's this thread, but for some reason topic starter deleted all his own comments, so I'm not sure if it'll be much of use to you.

I received an order confirmation e-mail a bit later after ordering the Witcher 3, in this e-mail there is also a link to redeem the code for "Neverwinter Nights: Diamond edition" and a link with code to redeem "The Witcher: House of Glass" comic on Dark Horse comics. You'll apparently receive this comic through Dark Horse and not with the rest of the goodies in your GOG library. The comic also goes by the name "The Witcher #1" on Dark Horse.
While typing I can see you've already received/found the e-mail, but I thought that I should still post this as this might help others dealing with the same problem.

I have one question though, maybe someone can help me...
The other comic "The Witcher: Reason of State" is in my library of GOG, though currently I can only see Part 1 here. Anyone know when Part 2 will be available? In the top part of the Description I can only see Part 1 stated, in the description below I can't really make out if we're supposed to receive Part 2 as well.

You should receive the code in your email inbox along with one for neverwinter night

After reading green.anger reply to my own thread, I've re explained my issue with said comic in the thread he linked