There are a lot of issue in your lighting, you can start with a 3d image but always take care, 3d have it's own problems. Plus it's difficult to have a convincing drawing at the end. You need to work more on the rendering, add colors isn't enought you will need to flatten some part and so.
But first : you need to start with a good 3d lighting if you still want to work with it. The one you have is all messed up, the light is supposed to come from the windows and door (where is the door by the way ?) so the shadow should be placed according to that.
If your render have some issue getting the right light place, shoot differents renders then place tem in layers in photoshop.