For a "standard" cross section, what you have shown in the image is exactly what you get. The section is a direct projection of the view it is coming from.
What you are thinking you need is an "aligned" section, but this doesn't work for your geometry. They are typically used for round parts to rotate all pertinent features in to the view plane.
In Creo, for aligned sections to work, your sketched lines and arcs must all go thru the axis you are rotating about. In your case, something like this where the red arrow is the axis of rotation and the purple arrow denotes an arc that center is on the axis of rotation and all the straight lines go thru center of rotation. This usually works great for round parts but is not usually applicable for non-round parts as you can see it stretches the geometry incorrectly.
