Recently I learned that the house I am renting is being foreclosed on. The builder of my house is the owner whom I paid the security deposit too. But they hired a rental company to whom I pay my rent. The bank came to notify me that the house is foreclosed and have already put it up for sale and have people coming through. Is this allowed? And can I still get my security deposit back?

If the property has changed hands then probably not. You can sue the builder but if he let the property be foreclosed, he probably doesn't have any money for you to collect from.

Yes, if the bank now owns the property they can bring prospective buyers with reasonable notice.

They also have to give you 90 days notice that you have to move.

What I would do is wait until a month before you will move and not pay that month's rent. See if they come after you for it.