In your screenshot, you're showing the date the item was performed or sold as October  2013.  The date of service has nothing to do with the date of invoice... other than that the invoice date has to be after it. ;-)

The top right of your Invoice form shows the invoice date... you have 1/11/14 there... and need to change it to the intended 2013 date.  The date appears to the left of the Invoice number on the screen.  Just modify that date and save.