Karma for you, desertgrandma, for always being happy to learn new things!
I use photoshop for most of my image tampering (and drawing and painting) but it is definitely NOT free.
Gimp is a free and really nice alternative, but it might be overkill and have a somewhat steep learning curve for someone who just wants to dress up their avatar...
Truth is, it is much simpler for me to make a new avatar for you than explain what to do, but maybe it's because I'm not really good at explaining (or so my frustrated technophobic dad usually tells me).
I'm sure there must be simpler programs out there, and someone else may have good suggestions for you.
In the meantime, I'll be happy to fill any specific orders you may have
or answer any specific questions that arise from playing around with any graphics software you choose.