SUMIF problems

Hi,



I am doing the following SUMIF

=sumif($r$60:$az$60,<=$i$3,$r$64:$az$64)

if i type the date it works-- however this date will change constantly and i cant update the date in the formula all the time
=sumif($r$60:$az$60,"<=01/01/2007",$r$64:$az$64)

r60:az60 is the date range
i3 is a date
r64:az60 is the numbers toi be summed range

i want to only sum the data if its corresponding date range is less than or equal to the set date in I3, but i cant figure out the correct syntax

help!

thanks