do you have the sources of the vendor software, or only the exe?
if you have the sources, you could simply ask someone to add the feature you
want.
if you don't have the sources, you would have to ask someone to write the
application from scratch.

that someone could even be a CS student or hobbyist programmer if you only
need to add a feature to available sources.

the important issue here is that you have to have someone who can test and
debug the new feature.
this cannot easily be resolved via a newsgroup.
I write test and measurement software for a living, and in my experience,
these things never work at the first try.
that is why the programmer has to have access to the hardware.