If you want the entire object to have rounded edges, it might be better to export it like it is and import it into Blender, where you can perform Subdivision Surface smoothing on it.

http://www.blender.org/

If you're not familiar with Subdivision Surfaces, here's a vid that explains it.
http://www.youtube.com/watch?v=ckOTl2GcS-E&feature=topics

Steve S