Highlight the column in question
Click on Conditional Formatting - Highlight Cells Rules - Less Than
In the field, enter 01/01/2013
In the dropdown, select the color you want
Now...everything entered in that cell that is a date Earlier than 01/01/2013 will appear in whatever color combination you chose.
For the "no entry = Yellow":
Again, highlight the column
Conditional Formatting - New Rule
Format Only Cells that Contain...
At the bottom of that dialog - Format Only Cells with: In the dropdown, Select "Blanks"
Give it the color scheme you want.
Play around with it. It is pretty intuitive.http://office.microsoft.com/en-us/excel-help/quick-start-apply-conditional-formatting-HA010370614.aspx