sroll widget and being fixed

hello everybody. i am using a widget on my pages as you can see.
my question wich i want to solve is how i can make the widget scroll while Scrolling my window down and up. I want to fix the widget on the side that it is Scrolling with the field the user is reading.

I hope someone can help me and we can solve the Problem together

The page I need help with: [log in to see the link]