。
Has she come here yet?
Literal
[topic-は] already here [to-に] is-come [question-か]?
きている is ~ている on 来る ('come') — a punctual change-of-location verb, so the construction yields the resulting state: 'is here / has come and is here.' もう in a polite question reads as 'yet.' The whole sentence is the kind of casual workplace check ('Has she shown up yet?') common in coordination contexts. Note 来る is one of the two highly irregular verbs in Japanese (with する); its forms (来る/来ます/来た/来て/来ない/来られる) need to be memorized rather than derived from the dictionary form.