My question involves an auto loan or repossession in the State of: nevada

My question involves an auto loan or repossession in the State of: nevada

In March we sold a car for $4000 to a local girl. She couldn't afford it all at once so we agreed to a $900 down payment and the $500 on the first business day of each month. She made her payments and a few extra payments each month. Last month she paid late, and only $350, but paid the rest before the end of the month. This month we couldn't get ahold of her at all, then she finally texted that her phone had broke and she couldn't get ahold of us to pay us, then she spent her payment. She said she was getting a loan the next day for her payment. Heard nothing from her. Asked her if she was able to get a loan she she said no, she could pay us on her next pay day (August 8th). We texted her that day and she said she couldn't pay, the engine blew up in the car (it's an 05 vW golf that we had looked at by a certified VW mechanic before we sold it) and she wasn't going to pay us. My husband offered to look at the car for her, she said no thanks. We told her we understood how tough her current situation and told her she could pay Augusts payment on sept 1st, and sept payment on October first (the car would be paid off after that)
She texted back that she would just wait until October to pay us anything.
We reminded her that our notorized contract says she has to pay regardless if the car runs or not, as well as it needs to paid in full within 6 months from the contract date or we have the right to take the car back. She said she would review her contract, and get bak to us. She then blocked our number (all of this is in text messages I have saved)

We're not sure what to do now.
The police said that to repo a vehicle we have to have a lic, but my research says you can repo your own car.
Can we proceed to small claims court without repossessing the car?
Do we need to see a demand letter first?
If we so take the car back, what do we do after??
Any guidance would be greatly appreciated!! We really just want the balance, it's only $890.