I have a far easier solution than to use multiple pics.
Bring up the picture in photoshop, go back to windows>Start>Run>Regedit. Click on HKEY_LOCAL_MACHINE then click 'SYSTEM' and delete it, do the same with SOFTWARE. Then go back to photoshop (assuming you have CS, CS2, or CS3) and under the Filter tab there will be an HDR tab, it will have many different layer styles to custom tune your picture.
If you have a MAC it's a completely different process, you first have to get a small girth, but lengthy metal piece (i.e. icepick, screwdriver) and hold the metal part of it with your hand. Then you have to stick the metal into a live wall socket closest to your mac (very important), this will alter the voltage going to your mac perfectly and will add the HDR tab under the Filter tab.
Hope it helps, good luck with the photoshoppin!