Are you talking about the Beach Club Villas? That is a DVC resort. Yes, March could be busy depending on Spring breaks, but even DVC owners can't reserve any earlier than 11 months out. If CRO has any cash ressies available you should be on an even footing with everybody else.
If CRO does not have that much space available and you are talking about renting from an owner, again you are on an even footing with everybody else. If renting from a DVC person is the case, you might want to jump over to the rent/trade Board to find someone who owns at Beach Club Villas (they have an 11 month window) to set up the details. Then they can make a reservation for you as soon as that window opens