Dude, do you want to export the graphs as images all at once and then have those images available for viewing? Do you want to export them on the fly? Is there a static set of spreadsheets around? Or are these spreadsheets created on a regular basis? From this data, you can determine what will be your best path.
But what you're doing is like saying, "I want to fly. How do I do that?" Uh....buy a plane ticket? Buy a plane? Get a jet pack? Get fired out of a cannon?
Ask a question poorly, and you'll be guaranteed nothing but poor answers. And by the way, from what I've been able to find, you can't do this from Perl -- at least not the way you've described so far. But you might look into writing a macro in OpenOffice.