IT guy issues aside, my recommendation is to keep working at using GIMP.
I went through a similar issue with 3D Studio Max. I had been lucky enough to get a slightly older version for cheap and really really enjoyed using it. Unfortunately as time went on, my version got older and older. I missed out on the newer, cooler plugins - it wasn't even a matter of my doing the same stuff with a bit more work - things like hair were just impossible. Then I stumbled upon Blender (
www.blender.org) - a freeware, open source modeller and renderer. The interface was/is completely, totally different. Different menus, different names for objects, even different layouts. It took some time, but now I'm proficient, and alot of the nifty features on the big price software are available on Blender. From what I know about GIMP, it's pretty much the same idea.
If I was a professional, I'd probably go with the brand name stuff (support, new features faster sometimes), but as an amateur I am really appreciative of the freeware stuff.