I have been facing the same kind of problem, but to call a sql script fron a pl/sql procedure and I don't think there is a way now to call host programs from within a pl/sql procedure. If its a simple sql query, you can try the HOST command.
HOST ......<command that run on the OS>
Or maybe writing a C++ or Pro*C or a PERL program for that might help. In case that you do find a solution or anyone has a solution, could you please mail the solution to me at email@example.com