Photoshop ? hogwarts texture

I have designed this picture:
It is an unfinished spot of the entrance to the gryffindor common room. After designing four staircases and four floors… here is a clip from the movie:
I designed this with 3-D stuido max.
Mainly… what I am working on, is trying to match the texture of the castle. It is not midievil castle, it is midieval church… white stone/plaster. Not only do I need to get a more precise texture, but obviously, like with the hand railing, the texture is getting stretched out across the entire thing and no longer looks good. What I would like to do is know how to get the texture to not do that… even if it means I have to design the railing in smaller block vs. one long block, I would like more depth and my bump map is not working too well for that. So, any suggestions or links to some good sites with that type of info would be great. Tyvm.