She placed a help-wanted ad for a housekeeper in the newspaper.
Literal
She [topic-は] newspaper [in-に] household-help [possessive-の] help-wanted-ad [object-を] placed.
求人広告 (きゅうじんこうこく) is a compound noun: 求人 ('seeking people/recruiting') + 広告 ('advertisement') = 'help-wanted ad.' 家事手伝い (かじてつだい) means 'household help' — someone who assists with domestic chores. The expression 広告を出す ('to put out an ad') is the standard phrase for placing an advertisement.