Fill without changing format?

I'm working on some reports containing references to cells in another worksheet. After inserting new rows I now need to change the references in all the cells after the new rows because they now reference the wrong cells. For example, cell J138 has become cell J141 because I added 3 rows, but it still references L138 in the other worksheet.

This is what the reference looks like now: ='[2001_ACT.XLS]2001 actuals'!L138 All I want to change is the cell reference at the end to L141. Easy enough to do manually, but I have three reports with over 900 rows and 6 columns each that need the change. I know this is probably a simple problem but I don't use Excel that much and am hoping someone can help me before Monday morning.

Thanks,
Laura