What makes you think WordPress provides a professional website? Are you sure? Many true web developers see WP as a load of junk. And "free" is not really the right vibe is you are looking for "professional"—well, not in my book, anyhow.
It's not all that hard to create your own theme if you can't find one that suits. But have you Googled this question? Something like "free reals estate wordpress theme" produces a lot of results. If you find something that's nearly what you want, I'm sure it could be modified to suit.