See EDIT3 below
If you look here: http://www.excelguru.ca/content.php?181 you will see excel VB code that can be run to do this. You can run that code from the command line using something like this:
c:\filename.vbs
That will start up VB script. VB Script is part of excel so that does not cost any more, there is no problem with licenses and you do not have to use Word.
I assume that you have Excel available Or is that what you mean by Office not being available? In your second question you indicate that Excel is available.
EDIT3:
Try installing OpenOffice (http://www.openoffice.org/). That will allow you to Open Excel documents without having Excel installed. It is free so there should be no license problem.
The following site shows you how to open the spreadsheet portion of OpenOffice from the command line: http://wiki.openoffice.org/wiki/Documentation/OOoAuthors_User_Manual/Getting_Started/Starting_from_the_command_line
The last paragraph of the following page indicates that you can convert from an Excel spreadsheet to PDF http://www.openoffice.org/product/calc.html
And most importantly this page shows how to convert an Excel ss to PDF using OpenOffice from the command line http://forum.openoffice.org/en/forum/viewtopic.php?f=9&t=32069