Superior limit to Universe extension

Hi to All,
concerning the universe extension is it possible to assume that the
maximum distance between two points in the Universe is
3.14*13.7billion light years?
Explanation:
in the earth the max distance between 2 points (e.g. north pole and
south pole) is one half the ring, i.e. 3.14*r (r=earth ray). In the
universe speed material cannot exceed the light one, so the universe
cannot have an extension higher than it's age, always travelling to
it's maximum speed... the light one...
What do you think about that?