I've never had the issue of exceeding the column boundaries of Excel 2003, I have however exceeded the row limitations and when I export reports that exceed that limit Crystal automatically creates multiple tabs in the spreadsheet for the additional data.
Have you actaully tried exporting to 2003 to see if it will do the same for columns?
The only other suggestion I'd have if that doesn't work is upgrade your version of Crystal (... I know :/ ) the new version supports Excel 2007 exports.