Hi, my name is Janis and I have gone through the situation that you are currently in and I would like to share some of my experience with you to provide you some initial guidance.
First, you need change the way you think about your company. From what I hear, you are reinvesting everything in the product development without having a sound business model. It should be clear that software development is really a never-ending story, so, rather than continuing on focusing on the technical side, you should start with the business side.
This, of course, means that you need to start from scratch. Start by identifying what problem you are solving and for whom. From there on, you should be looking for those, who are your immediate customers - whom you can sell with pretty much a single call. Provided, that you do not have a budget, you should be doing sales calls yourself in the beginning - with each and every sales call, you will either close a new customer or, more importantly, learn why they would not buy. Collect the reasons for not-buying and see what it takes to address those.
Then, depending on the budget required to address the obstacles and given the total addressable market size, it should be a good indication if you should be continuing your business development or no and in what direction.
I am here to help you, if you would like to get more hints and tips to build a sound business strategy and succeed in your business.