Looks a fine image...although I'm not sure the background shouldn't be black; as in deep space = nothing.
Expensive on Ink, eh?
The Gimp is a fine piece of software if you can only be bothered to use it - it suffers from most of the problems Photoshop and other clones suffer - too complicated for the average user to fix their dodgy photos.
Creating is a different matter - have you used Linux - or is this a Win-version?
- another art prog you might try is Inkscape ( Linux)...I think that's the name - it's a drawing/creation prog.
Good luck.