Have you tried the Singapore Math placement tests? It's free, though some parts of their approach and notation is quite different from U.S. approaches and notation, so don't let that throw you:
http://www.singaporemath.com/Placement_s/12.htm. Also, remember that Singapore Math is roughly 1-2 semesters ahead of a typical U.S. school, so a child in 2A is really operating at the 2nd semester of 2nd grade or even the 1st semester of 3rd grade.
Also, here's a set of free tests for grades 3-11:
http://scotthochberg.com/taas.html. (I know nothing about this organization or what they espouse, so please don't take this link as a recommendation of the group. I just like their free tests!) I realize they don't provide 2nd grade tests, but it might still give you a sense of where your children are operating. If they can pass the 3rd grade test, then they presumably can pass 2nd grade, right?
I have lots of reading assessment links (albeit many of questionable value), but not many for math. Sorry.
