Why "without using the header"?
You just
link or @import the stylesheet to the document which contains that markup and the browser does the rest.
If, for some reason, you
can't use the header (by which I assume you meant the
head section of the document markup), then you're only course of action is to use
inline styles (see above link).
(Well, actually, that's not entirely accurate. You
can link or
@import a stylesheet from within the
body, and so long as it comes before the markup to which it refers, you should get no rendering issues. However, that's a less than optimal approach as many consider that calls to external stylesheets should be contained exclusively within the
head section.)
Incidentally, that's some really horrible code.
Why all the b elements? Why the inappropriate nesting?
Show us the page design and how you intend to use that code (I'm guessing header and footer graphics or 'rounded' corners), and I'm sure someone here can suggest a more semantically appropriate use of code to achieve the same outcome.