Been bootstrapping a HaaS company for 3+ years after quitting my job. Some good SaaS-specific advice has been given above but the fact you've been struggling to develop a finished product in 3 years, which is almost an eternity in software, sounds alarming. I'd look into this oddity and assess your execution capability if you switch to full time. It does liberate you and definitely advances your business faster but doesn't make you a super hero either.

Also, consider the typical financial advice: don't quit before you have a 6-12 months cushion to face tough times. SaaS is hard.

The one word answer is: ask!

Make it a process to systematically ask every client for referrals. Referrals from happy customers are indeed one of the best ways to generate new business.

When and how to ask is a matter of taste and practice. Let me give you two examples which apply to B2B.

1. Ask as soon as your prospect has made his buying decision.
From Steli Efti, Startup Sales Guide - www.startupsalesguide.com
"When a prospect has already made a buying decision, say: Great, but I can’t let you buy just yet. Right now, we are a startup. This means we focus all our energy, time and resources on delivering as much value as we can to our customers. We don’t have a big marketing budget. If you are happy with our product, please recommend us to others who you think might benefit from our solution as well.”

2. Ask when you are about 2/3 of a project, or when you have significantly progressed in the relationship with your buyer.
Here is some great material by Alan Weiss:
- Asking For Referrals: https://www.youtube.com/watch?v=pXJXukZB94s
- How to maximize a referral: http://www.contrarianconsulting.com/how-to-maximize-a-referral/

Hope that helps. Put it into practice this week and let us know how it goes!