Okay, because your using a paid account style, I don't know if this will work. I know how to add a header to a free account style and I am assuming it will for a paid account style.

From what I can see, it looks like you have only altered the colours of the component style. You haven't made any major changes to the code, right? Because I am pretty sure with a paid account you add a header image by creating a new style and so forth.

However, the way I do it and this should work regardless, is to use overrides. You know how to use overrides, right?

In howto there is a tutorial explaining how to add a background image (http://www.livejournal.com/users/howto/8885.html) and then shift the journal contents downward (http://www.livejournal.com/users/howto/14978.html) so you can see the image.

Now I also noticed you have a background image which you won't be able to use if you use the above overrides. So if you do actually want to keep your background and add a header as well then I hopefully this tutorial will help (http://www.livejournal.com/community/overridehelp/312794.html). I haven't actually used that one so I have no clue.

So hopefully all that helps you :D