it is a tad on the small side, I can barely read it zoomed in full. Do you have a larger image or is that what you started with? I've learned to go big and worry about shrinking later although I'm still learning myself.

There was a tutorial or thread in here on making rotating brushes but I wasn't up to trying to figure it out at the time and I'm still not sure I understand the concept.

With Gimp to rotate a building I can tell you how I do it. Select a building you have already created and ctrl-C (copy) it (it will be saved as a brush in your drop down menu on the right which is pretty cool). You can then use the pencil tool and stamp it down anywhere or if you <Ctrl-V> (Paste) it you can use the rotate tool before you anchor the pasted image. It works pretty well.