When all else fails, (to the point it probably should have been tried first,) just trace it manually with the pen tool.
She was wanting a cut line. This is something done with a vector tool which Gimp is not. A cutline is a path in vector software recognized by a cutting plotter to cut out a sign, decal or transfer. It guides the blade. Gimp has some limited path abilities, but would not suggest Gimp for this. Maybe Inkscape, but not Gimp.Hello,
I am extremelly newbie here but, I couldn't help to want to reply.
Might I suggest you look into Gimp? It is a free photoshop clone (to the best of my knowledge). The things it can do are amazing!