Tara is torn; she doesn't want to leave Rose alone here with the Doctor in such bad shape, but someone needs to find a doctor. And frankly, she's not going to be help for much longer.

Softly, she says to Sam, "Doesn't Buffy's boyfriend - Kirk. He has a doctor friend, doesn't he?" Tara's never met Bones formally, but he does live in the Castle, so we can presume she's at least heard about him.