What is the ruling on working in a company where one must interact or be in seclusion with a woman, given the dire need for money and the importance of the job for one's future?

You must inquire about the nature of the work. If it involves being alone with a woman (khalwa), then it is not permissible, because khalwa with her is forbidden. However, if it does not necessitate khalwa and the woman is veiled, then working is permissible, provided one adheres to the etiquettes of lowering the gaze and refraining from speaking except when necessary for work and in a proper manner. If she is immodestly dressed (mutabarrijah), then working is not permissible, and one should seek other employment, while being advised to fear Allah and rely upon Him. For Allah grants a way out to whoever fears Him and provides for him from where he does not expect.