What I usually do, is write the GUI in another language, like powershell, then get those variables, and run perl with these as parameters. This way, the same perl script works if you want to automate things (non-interactively).

If you still want to use Perl, that works too, of course:

Win32::GUI or TK: How do I make Open and Save As file dialogs? (Win32)

Personally, I like AutoIT3 or VBScript