It seems likely that you are underestimating the potential market due to the design of your site. A few points:

1. The video walkthrough has no audio, and the notes are too small to read at the video's default size.

2. The upload links on the left aren't obviously links. Someone who is in a hurry could easily overlook them. (And no, they won't read the instructions or watch the video.) I would probably incorporate them into the main content area under a heading like "GIS Converter can convert:"

3. There isn't a straightforward call-to-action on the home page. Even something as simple as a big "Convert My File" button might be helpful.

4. Though the overall appearance isn't that bad, dark sites seem to have a harder time gaining users' trust, especially in business. Changing the color scheme to something lighter would probably help.