Figuring out control horns can be a bit confusing when you are first getting started in the hobby. Look at the attached diagrams and hopefully you'll get an idea of what you need to do. Basically, at the control surface end you get more throw at the inner holes and less throw as you move to the outer holes. At the servo end it is totally opposite, less throw on the inside holes and more throw in the outer holes. To fix your problem you need to move the pushrod to the outer holes at the control surface.

Hope this helps.

Ken