Congrats on launching.
Agree with codegeek . . . I think you're just at the hard part of building a SaaS of getting people to pay.
Check out http://restaurantengine.com/pricing/.
Google all the stuff Brian Cassel shared about growing it:
http://casjam.com/restaurant-engine-year-1-learning-things-t...
I think RestaurantEngine is similar to PropertyWebBuilder and you could learn a lot from what he had success with.
Go back in the archives and listen to his story on his podcast at http://bootstrappedweb.com/.
From what I remember he discovered that Restaurants wouldn't take the time to even setup their sites in the awesome builder they took so much time creating. They found they had to setup the sites for them, then charge monthly for hosting/maint/etc.
You could probably follow a similar playbook.
With realtors you should probably look for realtor companies that have 50 or 100+ agents and try to get the company signed up on an agency/company plan where all their agents would use your system. So you'd want to raise your rates for those, and have a setup fee for each one to cover the time of hiring someone to set them up.
Maybe provide a subdomain pointed at your server.
properties.bigrealtorcompany.com
Ideally you would get connected with reality offices where you are adding properties, allowing them to mark them as sold, adjust price, text, swap out images, announce open houses, make featured in the listings and you adding new ones so you get in a nice revenue cycle of $XX per add, and have a nice agency monthly fee on top of that.
Also checkout everything by patio11 here and on the web.
StartUpsForTheRestOfUs.com is a great source of good info.
Good luck . . . let us know how it's going.