With your filter you're actually removing 2012 from the dataset so will be unable to show last year with that implementation. I suggest you use a parameter instead of a filter. You can build a calculated field using the parameter to show last year as well. Something like:
IF YEAR([OrderDate[) >= [YearParameter] - 1 AND YEAR([OrderDate[) < [YearParameter] + 1 THEN 'Show' ELSE 'Hide' END
Put that calculation on the filter shelf and set to Show, it should then display the year selected and the previous year.