This time of year IF walmart has any left they will be in the close out /discontinued aisles and window A/C units will be DEEPLY discounted. Last year I saw 8,000 btu units going for as little as 59$ in the discount aisle. I suggest this because at this point YES you could call in inspections and have them write the LL a order forcing them to repair it , BUT At the soonest time legally possible your LL could then give you proper notice telling you to get out since you say you have no lease.