。
She just left the house.
Literal
She [topic-は] now house [object-を] left [just-now-ところ] is.
~たところだ pinpoints an action as 'just completed.' Combined with 今 ('now'), it tightens the timing further: she has only just walked out the door. The particle を on 家 marks the path or origin from which the motion verb 出る departs — Japanese commonly uses を with movement verbs to mark 'the place vacated' or 'the path traveled': 家を出る ('leave the house'), 道を歩く ('walk along the road'). Compare with the trio of ~ところ patterns: ~ところ (about to do), ~ているところ (in the middle), ~たところ (just did).