Help with Popen in 2.2

[Lowel Stern]

I have a problem that I can't seem to get around.  I hope somone here
can help.

snipet

import os

fp = os.popen('prog "stern:STWA" 1234')
ky = fp.read()
print ky[2:]

the above works fine. The quotes must be as shown they may not be
changed.   The problem is I need to be able to change programatically
the section "stren:STWA" and the 1234 section I have not figured a way
to do the substitution yet any ideas.

Lowel