Can you use a variable in VBA code inside an excel worksheet formula?

Is it possible for me to set a range say "AV1" in the formulas sheet to be equal to "fPriorDate", As String, that is in the date format that it is in, for example 30-nov-2009 (It cannot be converted into a number !), and then use that , cell value in the vlookup?

Yes and the same logic of building the reference using cell and static values would be applied.