If you buy cream cheese,sour cream,ricotta and yogurt they should all have expiration dates on them for more than 3 weeks away. Maybe not the yogurt but the others should.
I bought cream cheese recently and the expiration date is in May 2009. Sour cream is also in 2009. Look over what you buy and get the date that is furthest away. I have not had luck with freezing sour cream, never tried cream cheese.