Working with Excel 97 files in Excel 95

We are behind in the software upgrade department. As a result, many of our vendors send us proposals using Excel 97. We are currently using MS Office 95 (Excel 95 v.7.0). I have downloaded a viewer that allows me to view the file, but not work with it, convert it, or anything else. Is there a workaround/solution/fix?

Thanks,
franne