PHOTOMATIX is one of the top software for HDR processing. A Company called HDRSoft owns this software and continuously work to make it better.
Photomatix
Pro is available on Mac OS X as well as Microsoft Windows and primarily
designed to make the process of merging multiple photographs into high
dynamic range images and then locally tone-mapping them back to LDR
images, easier and more streamlined.
Different exposures are best taken as three different RAW files.
However, in some circumstances you can use one file and process the
different exposures from this photography.
We shall try this software for creating HDR out of single Photograph and share soon.