Fantastic work for a first model. I myself use ac3d and my first model(s) didn't look half as well done.
Something I wish I'd learned when I started was how to use the extrude option (top right under mode), well actually I didn't even know it was there. But yeah if you learn to use that it will be your best friend. You can really make whatever you want to with it. (The first thing you can try do it with is use it to make an actual roof which comes out a bit)
I'm unsure if ac3d 7 comes with pre-built-in plugins, but check the /tools tab for "uv mapper." (I see you may have already found it) That will help you get more complex textures looking good on your model (when used in conjunction with the /tools/texture coordinate editor).
Anyway, you're off to a good start! I also recommend learning/using Photoshop for your textures (also remembering to give each single model only 1 texture, using the texture coordinate editor to allow this)
Poloflece