Header image cutting off

Help! I’ve designed a custom header for my blog, but I can’t get it to display without being cut off. I’ve sized it at the recommended dimensions, and tried larger and smaller, all with similar results. I’ve found that if I show title and tagline with the image, it cuts off less, but the image is supposed to be the title, since I don’t have the paid version of the theme and want to use a different font.

I use Safari as my primary browser, but it looks just the same in Chrome.

Will I need to pay for the full version to solve this? Or am I just too green to know what to do? Any advice is much appreciated. Thanks!

The page I need help with: [log in to see the link]