Depends on your UY. If you add on now, you can bank them into your 2010 UY and they could be used for travel in 2011 if that travel is still part of your 2010 UY.
The other piece is that you might be able to get MS to chance around some of your points for your June trip. If that trip is in your 2010 UY, you could bank 2009 UY points, and then ask that they be used to replace the 2010 points (which you could then bank into your 2011 UY).
Good luck!