How to add a static pic under 'categories'

Hi all...

What I need to do is to have a particular post at the very top of the category page.
Like usual, when a visitor clicks on any of the categories, a page will load with the title "Archive for XXXX category". I need a particular post (even though it is an old post) to be displayed at the very top, followed by the (newer) rest.

I have tried using the 'Category Page' plug-in. But somehow it doesn't work.

I am hopeless with codes.

I am using WP2.8.6 and Theme version 3.4.4

I have just converted to this theme and at the moment, at the verge of giving up. Just can't figure this one out.

My blog is http://www.my-rainforest-adventures.com/

Would appreciate any help