that is not a 3.0 style it is a phpbb 2 style.
the best thing you can do is start with a new phpbb 3.2.5 style that resembles it in layout and maybe in colors.
then edit that style to look like the old one using colors and background images etc.
I am available for custom work on a donation basis. Please send me a PM with your needs.
Premium phpBB 3.2 Styles
OK, so what's the speed of dark?