her quest involves talking to colonel Hsu, who will give you another quest to find a ranger in Vault 3. another quest from her you can get is to find another missing ranger.
EDIT: oh, maybe you can get the quest directly from Hsu once you've found Anderson in Vault 3, tended to his injury and persuaded him to go back to camp McCarran. also, Vault 3 can be really tough if you don't have a high speech skill, I managed to buy the leader's helmet for my bounty, because I didn't want to fight my way outside through. there's gonna be a couple of captives on one of the levels, don't worry and open the cage if you can, they will sneak out on their own and the gang won't attack you.