Don't rush and quite your job. At the moment you have knowledge of two fields of both you seem to have somewhat of a passion. Think of what you want and if you can combine the knowledge of both. Gain some experience with the software used and the iner workings, especially if there are problems with it. In the mean time look at functions where you can combine knowledge of both fields, if possible in your company. That way you could grow to a more IT function while still maintaining your job. If you manage to learn and show the insides of your software you will be knowing insides as the goto person which could help your transition to another function.

I doubt somebody would perceive it as twice as hot. At some point it isn't perceived as more hot anymore. Maybe we need to do some test with people who experienced both.