Try this: (not tested)

select emp

, SUM(amount)

, '(THIS AMOUNT INCLUDES THE MONTHS FROM ' + cast(min(monthyear) as char(6)) + ' TO ' + cast(max(monthyear) as char(6)) + ')'

from @tbl

where monthyear in(112013, 122013, 12014, etc, etc..... )

group by emp