It's better to fix a CSS issue with CSS rather than HTML, so the best way to make the container stretch all the way to the bottom (or to wrap around its content) is to add this to your CSS:
border-style: none solid;
<font color='"Red"'>overflow: hidden;</font>
To center the header image, you'd do this:
<font color='"Red"'>background-position: 50% 0;</font>
margin: 0 auto;
BUT, be aware that having all that header information in an image alone is a really bad idea. Heading information like that is very important—for search engines, non-sighted users, SEO etc. Having it all in a image makes it totally inaccessible, and will serious hurt the site's performance.
One way around this is to place all that info in the HTML and place the decorative image over the top of that text. But a better solution is to remove any text from the background image and place that text in the HTML itself, using a fancy font if you need to.