The important thing is that whatever she's gonna do, she's gonna do it within one week. I think that it's gonna be much more specific then simply gathering info, the Others could sneak around doing that with ease.

I think most likely scenarios are
a) Kidnapping Sun (as she is pregnant)
b) Kidnapping Aaron (as he is the first child ever to be born on the island)
c) Kidnapping Desmond (as he has the power to see the future)

Can't think of another one, but I have a feeling it'll be none of the above and something that no-one suspects in the slightest.