Header image

So as you can see from the header image, I am not too savvy at blogging. I had the great idea to change the image on my header, and now I can not get the image to fit in the area. I check the "shrink to fit" box and that doesn't work. I have no other ideas on how to fix it either. Unfortunately I can't find the image that I originally had as my header. I'm out of luck. Does anyone have any ideas about how to fix my header image? Thanks!