Our dream house(no ramps all flat) just came up on Zillow as going to Auction

- at the moment it is in Pre-foreclosure .. according to Zillow
what is the best way to approach this.. tips tricks thoughts insight information . very welcome

We don't have cash, but we're pre-approved for a mortgage. I spoke to the old lady that lives there once a long time ago, and she declared she was never selling. I've tried knocking her door a couple of times since I found out, but no answer so not exactly sure of the situation. She doesn't talk to any of the neighbors so they have no clue. Going to leave a note in her mailbox. But considering this has hit Zillow I am sure every Tom, Dick and Harry is banging her door right now.

Would obviously love a bargain, but at this point just want to make sure we give it our best shot as we will be kicking ourselves forever if we miss this chance even if we pay over the odds.
At this point really don't know what to do so any insight or experience would be greatly appreciated.
The auction is listed as occurring 14th September 2018.
The owner of this property has been served a Notice of Sale.
Foreclosure type: Non-Judicial
Recorded: Notice of Sale: xxxxxxxx on 05/10/18