GGGGGgrrrrrrrr!!! Aaaaaarrrrrggghhhh!!! I have lost my long response to you 2x now because the system complained I was not logged in and then dumped my post.
In short to summarize, though... I had a similar problem HERE but it was the reverse. You may be able to use something like PHP's strtodate() function but I think you'd still have to use substr() to get the correct format.
If you are not a programmer, you can probably just use Word/Excel to split the dates into 3 columns, add preceding 0's and 19xx/20xx characters, rearrange columns to yyyymmdd order, and remove delimiters.