I Created Dashboard Prompt with 2column Like Year and Month.when User Select above year like 2013 Then showing msg or popup your select wrong value.At Same Time Month Also When select december(2012) Disply the message.
It would be more easy if you limit values as less than or equals to current year.
As you are expecting take more dev efforts and time.
Ex: year(current_date) in SQL at prompt.
Look for other simple options. Let us know updates.