Python COM -- What is the name of the file?

[Mike Brenner]

Does anybody know how to get the name of the file an Excel Spreadsheet is in?

For example, to do a file-save-as in tab-delimited format, 
it is necessary to change "C:\data\stuff.xls"
to "C:\data\stuff.txt", but I don't know where to
get the "C:\data\stuff.xls" from in any given spreadsheet.

It would even be okay, if I could just get the name "stuff" from some part of the COM object.

(And, of course, hopefully the same technique will work in Microsoft Project, etc.)