Ask HN: How do I sell my expensive niche software w/ no sales background?

A little over 2 years ago, I quit my full-time job and began freelancing. The vast majority of my work has come from one particular group of customers at a University. I've been paid 10-20k dollars on 3 separate occasions to develop a web application for this niche, I have another customer who will be paying me a similar amount in the fall when I work with him, and there is another customer who wants something similar but doesn't have the funds yet.

This niche is academic in nature and as far as I know the money comes from grants. I have never signed any paperwork, I have simply built what they wanted and been paid. I have a great relationship with these customers and have already discussed the fact that I might try to sell a product like this to other institutions, which they are fine with. I am confident that I can extract some core components that are useful in this niche, rewrite the app (there are things I want to improve), and create a product that would be useful to other similar institutions. However, I don't actually have many connections in other cities yet, nor do I have any experience in selling a piece of already-developed software for tens of thousands of dollars to people I don't know. All of my business has come through referrals. What I _have_ done is spent a few years talking to the customers, answering emails of the users of the app, developed several different versions of it, and been able to successfully charge money by the hour for development. So I feel like if I only connect a few more dots, there is a great business here. So now I'm trying to decide where to go with this, and could use some help.

So I have a few questions:

1) If a piece of software would cost tens of thousands of dollars to develop from scratch (possibly more when considering the development has required the time of many highly paid individuals), would it be reasonable to charge someone five figures for a packaged solution, and also charge a high consulting rate for customizations and integration with the customer's data? Note that this software isn't being sold to mom and dad or your friends, it's being sold to large, state and federal funded organizations, and there aren't many solutions out there.

2) How does one go about learning to sell? Especially a software product that is expensive, but probably wouldn't sell that many copies, maybe a thousand copies. Any books you recommend? Do I just find the proper contact at the institution and call them up? Tell them about what I have and show them a demo? Do I need to get a sales guy? Do I need to fly all over the country and show the software in person? Would someone be willing to buy an expensive piece of software based on a screencast and examples of a couple of other customers that use it?

So there you have it. I'm trying to make the transition from consulting to selling a product, have a couple years living expenses in the bank, and have someone willing to pay me while I work on it for the next few months. But now I just need to figure out where to go next. Obviously I will sell the first copy to the client I am planning to do work for in the Fall. But what should the next step be? My first thought would be to just start cold calling potential customers, which I have never done. Any help you can offer would be appreciated.