Could be sharper but I don't think it's too bad. Some of the loss of detail around the controls looks to be overexposure where the buttons all contain little lights.
So many variables to consider but if you can shoot at a time and location where the inside of the car stays pretty dark it gives you the option of freezing the movement inside the car with a burst of flash. Should work well bouncing off your pale roof lining.
If I'm shooting inside the car it'll be with a tripod, I can't imagine anything within my budget giving a better result.