Updating Excel Files...Old Template to New Template???

I Have a number(30+) of excel files based off of one template. I have since updated the template, thus making the the old ones obsolete. Is there a way to update the older files to use the new template without having to copy and paste the addition's row by row column by column?

None of the additions to the template will change the placement of existing data, nor will it change the data itself. It will however add Values to cells that were previously empty.

Hints, Tricks, or Ideas?

James