I think you should start to charge money for your product. If you didn't promess your beta testers a "forever free" product, you should start with them. I saw you said that people answered that "yes", they would pay. That is not enough, they must actually pay for it, real money.
If you think that wouldn't be nice to charge your beta testers, so the next step is two steps at once: test marketing channels and pricing.<p>You must know if you have a business, so you must learn if and how much people will pay and find out how are you going to find your customers.
Marketing is not a monster, just enumerate all possible channels (online: Adwords, Facebook Ads, SEO, Twitter, LinkedIn, content marketing, Pinterest, Press, etc. - offline: seminars, the obvious or weird strategies on <a href="http://fiverr.com/categories/advertising" rel="nofollow">http://fiverr.com/categories/advertising</a>, conferences, etc.). Don't try to be a visionary marketeer, just test every channel on small scale and see what works.<p>Oh, and you should read last PG essay: <a href="http://paulgraham.com/ds.html" rel="nofollow">http://paulgraham.com/ds.html</a>