First I had to select out the black frame, as that would have biassed the Levels hisogram; then in Levels (Image>Adjustments>Levels) i simply tweaked the highlight slider to the lightest pixels, and compensated slightly in the other direction with the Gamma slider (mid-tones). I also slightly warmed the tones, using a spot of red and yellow in Colour balance. I reckon there's a greater element of drama now, though it's all a matter of taste!
Regards
Will