can you please help me with the following questions...
Not sure I fully understand. You have an app that produces Postscript and you want to convert that to something else? If the application outputs the 'print ready' data then a new printer driver isn't going to help as the 'queue/driver' is just a way to get the data to the printer and not something that is creating the output file.
You might be best to look at something like: Redmon
This can take the output and spawn an new process. The idea would be that you have it output the Postscript to a file and then you launch some console .exe that you create against it.
Just a thought.