What is the ruling of the Sharia concerning money acquired through unlawful means and mixed with lawful money, which was then spent on furnishing an apartment and paying off debts, knowing that I have repented and reside in this apartment, and my husband does not own a home? And what should I do with this money or the apartment to rid myself of the sin?

You must repent to Allah Almighty for what you have committed by taking people's money unjustly. Repentance requires remorse, abstaining from the sin, and resolving not to return to it. You must return the money to its known owners. As for the unknown owners, their money should be spent on charitable causes with the intention of purifying oneself from illicit gain. You may take from this money if you are in need, and likewise for your husband if he is in need. If you fear your matter being exposed, then devise a way to deliver the money to its owners without its source being known.