I'd suggest using HTML for the interface. You've already got the skills and it is fairly easy to build an attractive look and feel for the thing. Going with HTML has the added bonus that the programs would be available from anywhere there is internet access. (Do I need to discuss the virtues of the client/server development model?)

You might try Win32::OLE. You'll need a working copy of MS-Word on the computer you are programming for. I don't think there is a module specifically that parses templates. You'll probably end up rolling your own.

Since they already have their stuff in Word, Win32::OLE may be your best bet. You can probably do the same (or similar) with PDF. (Generate postscript, send to ps2pdf or equivalent). Heck you might even be able to make templates out of PDF files. I know there's text in some (though not all) PDF files. Perhaps a monk higher up the food chain would care to comment?