Well, while the over 2's are hard to fill you may luck out in finding a family that needs an under 2 and has an older sibling. Just like this family there are plenty of families out there that have a spot for their current 2+ child in a home daycare that won't have room for the new infant.

I think you are more likely to fill the 2+ spot with a sibling set than to fill the over 2 spot with no under 2 spot open.

Start advertising now. Advertise for an under 2 AND over 2 spot and see what you find.