yes do what dave suggests and add a bevel to the upper diagonal edge and along the red arrow this will add sharpness. Then you will need to turn any resulting n-gons into quads or tri's.
I made a quick mock up of your topology and below are some screen shots of the basic idea we are talking about...
Here I have tightened up the leading edge and the inside corner edges but you can change the bevel strategy to suit your needs.
Cheers.
"If I have seen further it is by standing on the shoulders of giants." Sir Isaac Newton, 1675
Last edited by ctbram; 03-09-2012 at 04:58 PM.