Alper,
I had a few problems with this photo and I decided to do a workshop to show you how I'd change it.
Here's what I did with Adobe Photoshop CS3:
I first has a problem with something this nice being in landscape format so I changed it to portrait mode with a much needed crop.
I then brought back some light on the top left of this image as it was too dark in that area. I noticed that the color looked pretty drab on the bottom third of this photo so I added some. It wouldn't have been complete with the "natural frame" I gave it. I hope you like it!