Can you get more up-front commitments from current clients, prepay for a year for a discount? This could let you pull the plug now on the day job and focus fully on your own project. The idea of that part of the class was that businesses often both customer and even suppliers to fund themselves, and that alternative and creative financing solutions can be negotiated.

Also, as others said, you might be able to find a small business loan since you already have cash flow, via traditional or other methods (online lending).