The question is a little bit unclear for me. And I doesn't speak Applescript.
But if I understand you right, you want to do something like this:
i want to export files into my current open location.
when export eps. I like to have a specific name at the end of the file name.
for Ex: filename_EPS.eps
I work these this in applescript but i am getting ( filename.ai_EPS.eps )
Sorry, like I said before: I don't speak Applescript.