If I remember correctly (and I defer to Suzi if she knows differently), if you/we (since we're in the same situation) haven't finalized in 2012, we could claim expenses from 2011 but not 2012. You can claim expenses from the same year if you finalize in that year, but otherwise, the expenses must be claimed from the previous year. So, when we filed in 2011, we claimed our expenses from 2010 but we couldn't claim any of the 2011 expenses until finalization (or until this year - the same for us).
I don't know if what I've typed makes sense. It's very complicated. I would love to know if we could count the expenses paid in our failed match as an attempt but whether that's possible I don't know. I think it would be difficult to do, if even possible, since you have to have a SSN or adoption ID# for a child to claim it as far as I can tell.