Well because the wallpaper uses only one color and the rest are greys you can make it any color you want without a problem.
Download gimp (free photoshop like prog)
http://www.gimp.org/Open the pic in it, go to the Color drop down menu
then hue-saturation, adjust hue slider to any color you want
then go to File then export to save, can save it as jpeg
jpeg menu can be 98 to 100 percent quality but under advance de-check all the boxes