I've said this before, and I'll say it again. I've seen the best teams on the circuit go forever without a sponsor, and I've seen the worst teams on the circuit get major sponsors. It's a crap shoot. You have to market yourself, and then, it is still a crap shoot. If you are really serious, I'd get in touch with Michelle-May Schmidt. She does this for a living, and she is very good at what she does. She is also very intelligent and a pleasure to deal with.
My $.02 for whatever it is worth.