Hi! I don't quite understand Image 1, showing the lowpoly with the square insets. Is it missing a modifier? To troubleshoot, I would apply modifiers and check the resulting topology and UVs. If you want another pair of eyes, could zip meshes/problematic area and attach the file to a post.
Well, it's not really the door inset that's a bit small, but that entire face of the building. As you see in the concept, the windows are all wider than they are tall.
This thread answers a lot of these questions http://www.blender.org/forum/viewtopic.php?t=14688&view=previous&sid=c79d17275e7497e67e88add47474a118 Including the inset one: