You could screenshot each frame of the would-be-gif and go edit it so you only have your sprite.
The go into adobe image ready or something and animate it frame by frame.
I've never used Firewoks so i don't know how that would go.
o.o; You would seriously screenshot each and every one of the frames he wants in his sprite?
If you want a walking sprite you find a sprite simulator and use that. Ragnarocks for example gives you moving sprites if you want to, you just have to save each frame. But it's a lot less trouble then taking screenshots in game especially when the game could run up like 24/fps.
Also there's sprite sheets of every single job, hairstyle, and color available for download. Build up your charcter with those and use them to animate, it's still a lot less hassle then taking screenshots