Up until version 2007 Microsoft Excel did support XLR format from MS Works and could both open and save spreadsheets in this format just fine. Unfortunately, this is not the case for latest versions of Microsoft Office and same foes for the usual alternatives to Excel, such as OpenOffice.org Calc or LibreOffice.
A viable option would be to get your hands on some old version of Works. It was commonly bundled together with laptops and new computers so you may even have some old Works installation CD at home.
Updated: July 14, 2016