Layout Question

I’m keen to use the standard main content/sidebar layout for a new site, but I also want to have an area above those two divs that will be as wide as the lower two combined, and will contain a different image and paragraph of text on each page. However the only way I can think of to produce this is to insert the appropriate HTML code into the WordPress page area, which kind of defeats the whole purpose of having WordPress installed anyway. Apologies if this isn’t clear, but if anyone knows what I’m on about and can offer any suggestions, I’d really appreciate it.

Cheers,

Chris