It is impermissible for a Muslim woman to work in a place where there is intermixing between men and women. Rather, it is Wajib (obligatory) on her to abide by Shar`y (Islamic legal) Hijab and avoid gatherings of men. She has to find Mubah (permissible) work that does not involve anything Haram (prohibited). It is worth mentioning that whoever abandons something for sake of Allah, Allah will give them that which is better than what they missed. Allah (Glorified be He) says:
And whosoever fears Allâh and keeps his duty to Him, He will make a way for him to get out (from every difficulty).
And He will provide him from (sources) he never could imagine.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.