You should try PNGs. They're about the same quality as bitmaps, but they conserve a bit more space. Most pixel-art based programs can use PNG format and many programs (RM2k and RM2k3 included (not sure about XP, but it probably does)) will allow for PNG use.
By the way this sheet looks, it looks like the "fire" is hair, when it looks more like a crown to me in the reference pic. Also looks like the scouter (the visor on his darker eye) looks like it's actually part of his face when it probably isn't.
But for a first attempt, it is not bad at all. Sorry if I sounded nitpicky.
It may sound somewhat irrational, but I suggest finding more reference pics, from different angles if you can (this should be obvious, but the higher the quality, the better). It can help make finding little details much easier. Obviously you won't be able to put in every single detail on small sprite like that, but it doesn't hurt to add a little more detail.
_________________ The Local Video Gaming Lunatic
Recent stuff I'm into:
Watching: A Certain Scientific Railgun (ep.14, stalled), Hoshi no Kirby (ep. 71, stalled), Nazo No Kanojo X (ep. 8), Acchi Kocchi (ep. 8)
Reading: nothing