Actually I am working on the assignment as we speak and I have passed the part I Beta in 2007 so there is no connection between the Part I and Part II in time. You just need to pass Part I in order to step to the assignment.
Further more the assignment can take as long as you wish , there is no time limit there.
However the essay voucher you bought (in January ? ) can be used just one year so you can use it until January 2011 only therefore you need to finish and take the essay before January 2011 (or buy another essay voucher if the assignment takes more time).
Good Luck !
Better, faster, lighter Java ... you mean Ruby right ?
SCEA5,SCBCD1.3,SCWCD5,SCJP1.4 - memories from my youth.