What to do with my '07?

So I inherited my grandmothers '07 prius, it has one battery module that is failing and might need a new 12v as well. It has the RToD and currently wont start without a jump. I'd like to sell it and get a chevy volt but I don't know what is the best option for me and for the future owner of the car. Also, used values seem to be all over the place so I'd love some advice on asking price. The car is in pretty good shape; 112k miles, new paint last year, interior is a bit worn with a tear in the rear seat and stained cargo mat. These are the options I'm considering:

1. Sell as is
2. Recondition battery with a Prolong kit. Then either resell the kit or sell it with the car.
3. Replace battery with a craigslist unit. There's someone selling one for $600 (or $500 plus my core). They say its in good condition out of an '09 with 107k miles. Are craigslist battery sellers sketchy? I figure worst case I can just use a module from the new battery to fix my old one.

Either way I obviously want to be very transparent when I am selling the car about the health of the battery and will hopefully be able to show the buyer a clean bill of health via the Dr. Prius app as this car has a lot of life left. I guess I'm just unsure whether to get a new (used) battery or recondition my own. I also have no idea what the car is worth once it is running. I initially thought about 4k but I've seen similar ones for more than 8k from dealers. Any advice appreciated.

 

Thanks I will message you, although I am down in Portland.

 

I'm getting an error when I try to PM you, perhaps because my account is so new. Maybe you can try messaging me?