Okay, so I added:
$head = get_block('head', false);
echo $head->getCssJsHtml(); // All CSS and JS files defined in your Magento head
before the </head> tag and that made the header appear like I wanted, but it's caused all my text to center itself. Here's what it looked like before the code: http://cl.ly/image/11273G2W3701
and here's what it looks like afterwards: http://cl.ly/image/0X1I3D2h0M07
You can see how all the text is centered. Why would that be happening?
Also, my header doesn't reach all the way across the screen when I go to a blog page. It's fine for blog posts, but not pages. Here's a post (which is how it should look): http://cl.ly/image/0V0J0m3n1l2S and here's a page: http://cl.ly/image/103g20263W1b. You can see that viewing a page puts the whole thing in a frame or something.