This doesn't sound like a project that would be particularly hard to print. But you need to find some software that will let you design it without too much trouble. I'm not sure that either of those programs are really intended for that sort of thing. They both are focused on mechanical types of parts; what you need is something that's intended for organic modeling. If you're limiting yourself to free programs, look at something like Blender, or Sculptris.

Andrew Werby
www.computersculpture.com