Animation of a mechanichal application

Hei to All. I have a CAD file STL ; OBJ ore files like this from a gearset with piston. The file is from an freepiston engine that need to be animated and rendered. As a outputfile I need a file that I can work further on link wmf, or a flash file ore a file that I can use in Magix. This will be a first part of a bigger presentation on the web and Youtube. There are to pistons that are working in countermoving direktions, and a gearset that looks like a differential. In the centre is the main shaft that have to rotate. The file that you will get looks more like a professionel CAD file like the pictures i attached. The rendering is importand. clear colors and a nice background. I will first have the mechanical principal for the community, please feel free to contact me.