WAGNER-
I created this custom background from a cropped picture I had in my folder specifically for a Demo for George's Tobasco Tours site a couple of years ago, which I posted (along with a couple of different versions) to illustrate the principle of layering and layout
[Link To Demo Site].
I made it large enough so when it "tiled" it would still be pretty much under the page background and it would not be noticed how the pictures had a "fuzz line" where they met. However, to make a page background (the white area where you place Content on top of), you simply make a "shape" and size it accordingly: you can even add a colored border to your shape, or overlay another shape which you add texture or gradient color.
You simply use "layering" to assemble a composite look ... not difficult. Just make sure whatever is supposed to be on top (like hyperlinks) is 'brought to Front' otherwise they won't work.
Using this background is incongruent with your site theme (real estate), IMO, and it really is not nice to use it without citing source or first asking!