I reckon the way to go light-wise would be to see if you can dim it a little bit, and make it more directional. For example, move it further from the window, take the shot at a different time of day, or consider using a normal desk lamp to get the light you want (make sure you adjust the white balance for a tungsten bulb though). Basically you want to be aiming to get a bit more shadow so that the texture is brought out a bit.