Do you want to reload a document in QV Desktop only? Then you can leave your PC on and use Windows Task Scheduler to create a schedule for reloading your document.
Do you have a QlikView server and no Publisher? Then check out Massimo's suggestions.
Do you have a QlikView Publisher at your disposal? I'll assume that you know how to use it; just create a task, add a Trigger "on a schedule" and select "Monthly". Then choose the months (and days) on which you want to reload your document.