[SOLVED] Just left and right borders on header image?

I'm working on www.exeterbabyactivities.co.uk and I'd like the blue line I have left and right to continue up onto the header image. I can do this in photoshop but that seems a bit clumsy, is there a way to just add left and right borders to the header image?

I'm sure you are going to say add to the css but although I know the syntax for the width of the border and colour I want, I don't know how to tell it to apply it just to the header image.

Any ideas appreciated!