Placing Only One Adsense unit In First Category Post

[mmafight]

Hello everyone and thanks for the quick replies on all of my threads. Here is another topic I haven't been able to figure out...

We all know that there can only be 3 Adsense units per page, so here's the problem:

I've been able to add one Adsense unit at the top of my single posts, but I haven't been able to keep it this way in my Category pages as well.

How can I make only 1 Adsense (300x250) unit appear on the very top of my Category page only, just the first post? For some reason, it keeps adding a second Adsense unit on the second post of that same category page.

For example, if you go to the following link:
http://www.mmafight.com/category/mma-events/

You will see an Adsense unit right above the first post and if you scroll down that same Category page, you will see a second Adsense unit. The reason why I don't want that second Adsense unit there is because I want it to appear on the sidebar instead. But because it shows up in that second article/post, you'll see a blank (white) box on my sidebar. That's because there are already 3 Adsense units being displayed on the page, but I don't want it that way.

This also affects the other posts in that same category page because it creates a 300x250 blank space.

Hope someone can assist me with this, I'd greatly appreciate it.

Thx in advance