You should probably contact the property management company about your security deposit, however. Hopefully they still have control of the money and never turned it over to the owner that was foreclosed upon. Usually they don't refund the security deposit until the tenant vacates the property, but this could be an exception.
My best advice would be, if you cannot contact the mortgage company in the next week or so and arrange for a new lease, plan on moving and start to look for another place. Better to take that bull by the horns rather than risk being homeless or having to move into a place you don't really like!
Hope this helps!
Berkshire Hathaway HomeServices
The Tonnesen Team - with over 30 years of experience helping families call Las Vegas "home!"
I will suggest to keep your lease agreement handy and your last month receipt, chances are that they will contact you and at that point they new mortgage might even ask you to sign a new lease.