This is your Home folder. Go to the Go menu, choose Home, now change the layout to what you like, including the size of the window. Now close the window (don't do anyting else, just close the window) Now when you go to Home, the Window will be the layout as you left it, until you Change it. I've had the same layout on my Home folder for about 2 years, and it does not change.
hint: always return to Home the same way, Like choose Home under the Go menu. It will also generally be the same layout, no matter how you return to it. The first step is always the same, Change layout, then close the window as the next step, that will freeze that window layout (or should) You can use this same tip on ANY window.