Use Conditional Formatting....

Select the cell and go to Home|Conditional Formatting, New Rule.

Select "format only cells that contain"

in the Rules description area...

Cell Value is >> Equal to >> =TODAY()

Click Format and choose from Fill tab.

Click Ok, click New Rule

Select "use a formula to determine which cells to format" then enter:

=AND(DATEDIF(A2,TODAY(),"m")>=6,DATEDIF(A2,TODAY() ,"m")<=12)

where A2 contains the date...

Click Format and choose from Fill tab.

Click Ok, click New rule and repeat as above with Rule

=DATEDIF(A2,TODAY(),"m")>12)