Two things you can try to get the information back -
1. You can try to open the Excel file in Microsoft Word --- Yes I know that seems like a stupid thing to do, but trust me it works. You loose a lot of the formating, but you'll get your data back.
2. Download Open Office and try to open the excel file with that ... if it will open, resave it (as a new file) and you should be able to get back to it in Excel again...
If neither of those work - you might be up a creek and sinking.
