The front camera is very low res, and was designed mainly for web-cam use (like Skype video calls). You'll never get a good picture out of it, since it's not designed to do it.

With the new FCam stuff you should be able to use the front cam to snap self pics, but it's still going to be grainy and low res. You're better off blind-snapping a pic without the display pointed at you. Or, start a video and video-shoot it. At least one of the frames it captures will be a nice picture at about the same resolution as the front camera.