Unfortunately, there is probably nothing that you can do.
Even if the individual who sold the car maintained the transmission properly, there is still a chance that the transmission could have failed unexpectedly.
And then, there is the likelihood that the trans fluid wasn’t changed every 30k miles, as we always recommend in this forum. Because few maintenance schedules still list that vital service, most car owners don’t have their trans fluid changed every 30k miles, and that omission will inevitably shorten the life of the transmission.
Did you obtain hard copies of the car’s maintenance? Do they list trans fluid changes?
Before you commit to a trans overhaul/replacement, try to get comparative pricing from one or two independent transmission shops, as they usually charge less than dealerships do. Just be sure to avoid chain-run trans shops like Lee Myles, Cottman, Mr. Transmission, or–God forbid–AAMCO.