#1 update your WordPress to the latest version, ditto Atahualpa.
#2 Remember, when you update your Atahualpa Theme, you will have to re-upload your banners as they revert to the default banner of berries etc.
#3 In Appearance/Atahualpa theme Options, Add CSS/HTML Inserts (down near the bottom) add:
could just as easily be
It depends where you want to upload it.
At this site:
I did that, and I made the banner a .png with a transparent background.
By the way, I cannot open your ipenguin page.