It's pretty easy to muck around with the CSS and the class names of elements with jQuery. That's certainly how I'd go about it.
You can choose to either expand the target section in place within the page; changing its dimensions, perhaps position, and amping up its font size. Or you could show the section to be expanded on a floating display (like a jQuery UI dialog). Depends on the specifics of your requirements and what you want to do.
But it doesn't sound like anything that's too onerous to accomplish with the right tools.