I actually always saw this as coincidence with her being the "original past version" of this woman, who's unaware of her future.
Whereas your interpretation makes much more sense I have a major problem with it: causality! They cannot stop the outspread of the virus because this would prevent Bruce Willis' and her future actions and therefore the whole movie and their stopping of the virus. And he already let it free in the airport when he opened the glass, didn't he?
Well most movies about time travel don't care about such causality problems, but especially Twelve Monkies is one of the few films (or the only one? maybe Source Code in its own theoretical physical interpretation) I know that handle causality in a plausible way. So I'm pretty sure in the context/story/universe of the movie they cannot prevent the outspread of the virus because all their actions are already prescribed, like Bruce Willis' death in the airport has always been prescribed.
But well your interpretation still makes sense, so I think they could still try to stop him (the characters are still unaware of the causality problems) without success or even heal it in the future, where the story is still open.
So yes, she's likely to be the insurance to stop him. But again, she will not be able to achieve it.
EDIT: In my coincidence-interpretation the "insurance" remarks could also be just a symbol for her, one of the scientists/leaders, being an ordinary citizen in the past, in this case an insurance agent. Similar to the symbol of the Holnist leader being a former copier salesman in The Postman.