You can change the background or the font color depending on what you want
For font color:
=IIF(Fields!YouDateTimeColumn.Value <"TheDateYOuWant", "RED","Black"))
For background color:
=IIF(Fields!YouDateTimeColumn.Value <"TheDateYOuWant", "RED","White"))
If you want to change the dolloar format is the letter C
For further reference on conditional formatting you can refer to this link
http://technet.microsoft.com/en-us/library/ms157328.aspx