Oh hell you're good at MS Paint but... your talent is wasted if you continue on MS paint. It's like you are on the way to a race driver but still riding a tricycle.
I'd really like to see some of your sketches w/ pencil or other non computer edited stuff.
If you want to do a step between MS Paint and Photoshop, I recommend Zoner Draw 3 (vector Software, available for free at zoner.com, just give it a try. Otherwise... just get a pencil and a sketchpad, that's all you need. I really like the BMW!!!
And the pic in your sig... is that your ride??? It looks awesome!!! I'd like to see more pics of it also!!!