If you don't want to parse & rewrite it, then you'll want to use Win32::OLE as mentioned by Corion. As you mention in Re^2: Append row into existing excel file, there's no function in Win32::OLE. That's because OLE is just a Microsoft-standard interface for talking to objects (not exactly the same as the objects in OOP, but not terribly dissimilar).

The general procedure there would be to tell Win32::OLE to create an Excel application object for you, and then tell Excel to do what you want it to do. Note: You can turn on "macro recording" in Excel, and then add the row(s) you want. Then turn macro recording off, and you can then look at the VB code in the macro to see what you need to tell Excel to do.

If you search around, you'll find plenty of links on 'convert VB to perl' which include some Excel-specific examples in the threads.