
If she is afraid of the car itself, treat her while standing next to it.
When I got both boys at 5 months old, they had never been in a car and both would drool excessively to the point where they looked like they'd been doused with a bucket of water and even walk skittishly past it. Infact, on the day I picked them up, the 11 minute drive ended with two huge puddles and 2 even bigger piles of you know what on the sheet I'd put in.
I tried not feeding, sickness tablets, anti sickness treats, ginger nuts, DAP spray, regular rest stops etc but this is what worked in the end.
Use a high value reward like chicken, ham etc and stand next to the car. Have her on a loose leash and call her towards you. Everytime she comes over, reward her and fuss her. Then once shes got it, try with an open boot/door. Once she's happy with this, try feeding her her dinner in it. It will be a long drawn out process but well worth the effort. Lots of short trips to somewhere nice - even down the road to the park will also help.
My boy didn't get over his sickenss until 14/15 months old but he loves the car so much now that jumps in the boot for sneeky nap just as hubby starts to hoover the interior!
Stay positive. She will get better.