3d guitar drawing, what software to use?

Hi everyone,
I'm from Italy, i'm 27 and i build guitars in my free time.
I've just builded and handcarved a guitar top and now i'd like to draw it in 3d so that i can carve it on a cnc machine next time.
The cnc loads stl and dxf files.
I can draw on Autocad quite well but i had some problems drawing it because it's shape is quite irregular and probably i don't know the correct tool to use.
If you think that another 3d software would draw it better or easier it's not a problem for me to learn to use it.

Now i'd like to link two pics of the top im talkin about but this is my first post so i can't do it..

Thanks to everyone for the help

I uploaded a pic of the guitar top in my gallery, you can find it there

I'm regularly modeling stuff for cnc machines. I use 3dsmax but I suppose that it can be done in any soft that can export OBJ file

Hi! Thanks for the answer
What do you mean with "OBJ"? Is it the extension of the file?
So im going with 3dsmax, i can import the 2d shape i already made on Autocad.
Any hint on how to transform the 2s shape into a 3d one? What tools will i need?

Thanks

Yes, by OBJ I've meant extension If you want to transform flat shape to 3D then use Shell modifier.