Rename Files in Folder - Change Date Format

I am brand new to programming and have read two text books on it and am having difficulty figuring out how to do this. I have files saved with the mm-dd-yy date format, and I want to rename the files with the yyyy-mm-dd date format. I have created a spreadsheet with the first column with all the dates from 9-1-10 - 10-31-11. The second column has the same dates in the new date format. There isn't a file with every date in that range.

Any suggestions?