Nothing like resurrecting an old post LOL
Unless you have a printer you can't do black and decals unless you double lay them with the different colours in vinyl layered one on top of another.
To get the small amounts of vinyl you would need for personal use on your own car just go along to a sign writer and ask to buy small lengths of vinyl.
My mate has a Craft Robo, he can get text down to a few millimetres as I can on my Stika machine.