。
She wanted a better job than scrubbing the company's floors.
Literal
She [topic-は] company [of-の] floor-cleaning [than-より] better job [object-を] wanted.
まし(な) is a useful word that doesn't quite line up with English equivalents — it means 'better, preferable, less bad,' often as a comparative concession ('not great, but better than the alternative'). より marks the comparison's standard: 'better than X.' The phrase 床掃除よりましな仕事 ('a job better than scrubbing floors') sketches a quietly bitter scene of a worker stuck with the menial assignments. 望む ('to hope for, desire') in the past form 望んだ tells us this was her wish — whether she got it is unsaid.