volterre???

Having a car I'd also consider staying at an agriturismo. Most are located quite rurally but offer a special experience. Also, many will have a pool which could be quite nice considering the time of year you're going.

We stayed in the area of Barberino Val d'Elsa which we found to be quite central to explore different places in Tuscany, including a day trip to Volterra. Barberino is quite small and doesn't offer that many restaurants or opportunities to shop (you can do the shopping in nearby Tavernelle). But small has its own charm.

Cars are great, and fairly necessary, in Tuscany. But they also make it hard to stay inside a town of any size because of the difficulty in finding a parking place near your lodging, and the difficulty in driving into and out of town on any days that you want to go somewhere outside of town. The narrow old town streets, and multiple one-way streets, can make driving a real headache.

I'm assuming when you say "volterre" you're speaking of Volterra. They have a multi-level parking garage right at the edge of town, so you could park the car there a few days (with accompanying charges) if you're just planning to stay in Volterra all that time.

But if you're planning to take the car and do things outside of town, you'd be better to stay outside of town in a place that's easy (and free) to park, and just visit Volterra one day, parking in the garage mentioned above.

As Beatrix mentioned above, agriturismos are nice in that they are easy to drive to and parking is plentiful, easy, and free. The drawback of an agriturismo is that you're outside of town, so after dinner you could be driving back after dark. (Unless you cook dinner at the agriturismo apartment...it can be fun to shop at a local store and do your own cooking some of the time. With a little looking you can find an agriturismo that allows a 3-night stay.)

We stayed a while in Greve in Chianti at the downtown hotel Casa al Sole. Greve is a small enough town to let us have free parking right by our hotel. It's a great place (though not as ancient and interesting as Volterra) and easy to drive into and out of. Greve is between Siena and Florence.

I am also staying in Volterra soon. We looked at a highly rated (on another travelsite) B and B/Hotel just outside of the wall of Volterra. It is called Villa porta all'Arco and I believe they have parking.
This might solve your problem.