First, you have tons of unused uv space. Second, I personally would take some of the polys out of the roof and throw them in the leg thingys on the sides. You'll see the sides more than the top I think. Don't add more sides to the legs, but more edge loops so you can make them interesting and less geometric.
If I were you I'd arrange my uv's for that like this:

No, you don't have 4 seams, because you'll paint that quaded circle just like you would a seamless texture (and you don't see the seams on those now do you?).
Looks like a good start though, could polish out to look pretty nice.