Unfortunately you bought the program. You could have obtained it here, at no cost, as in free.
http://www.demonoid.com/files/details/2296079/47538225/
Might be a slightly older version but it is completely functional and the price is right.
I differ with you greatly about the quality of graphic renderings as compared to SketchUp.
Realtime Landscape Architect is really for garden and landscape level designers.
I am not one of those but enjoy playing with it from time to time.