ElegantTheme modifications

Hello,
If someone can help me and give advice on this would be very grateful!
Thus, I have sat sajt.com where there is the issue http://www.elegantthemes.com/preview/ElegantEstate/
On the website are houses and flats. What I need is that when the site open site.com that offers two links: flats and houses.
Both need to look the same (header, footer the same theme) In addition to the one we manifest posts for housing (as well as menus for the flats) and the second
just a house. Means practically the same site just with different content and links. Of course, I could install 2 separate wordpress site in sajt.com / house and site.com / flats and the sit.com linking on these two. But then if I change for example the color on one site, I have yet to work on another. Does anyone have an idea how to do that to me shows the same site only different posts for houses and flats, as well as different menu depending on whether you choose a house or flats? I am aware that I must change code this theme, but I would not change engine and the wordpress code and it should not be changed.