Be careful with what you choose to sew this button on with. The metal edges are likely to be sharp enough to cause the thread to fray over time. Do you have any teeny tiny ginder bits or files to smoothe the cut edges with?
I have gimp right now. And I am still in pre-school as far as knowing how to use the software. I want to have more understanding and facility with this program before I invest in something like Corel. I know that Corel offers free 30 day trials.