How To Automatically Submit Online From CSV Sheet On Schedule?

How To Automatically Submit Online From CSV Sheet On Schedule?

I have a Wordpress blog and a simple PHP script that lets me create posts
on the blog by uploading a CSV file.
To upload the file, I just go to the script installed on a subdomain,
click 'choose a file', choose the CSV file and hit 'send file'.
I want this to be done automatically, at regular intervals. For example,
every 15 minutes it takes the next excel file in a directory and uploads
it or better yet, it takes the next 50 lines of a csv file, uploads them
and deletes them from the file.
Of course, I could try to rewrite the script itself to do this, but am
looking for a simple solution. What is the most straightforward way of
doing this? Javascript? An excel macro?
I appreciate and comments or suggestions.