Amanda, I am very sorry that your kittychild freaked out. Are you positive that it was a seizure or was she just toally and completely freaked out due to being in the crate and the car ride? Is she an indoor kitty that never ever goes out or does she go outside?
If she is a total inside kitty and never ever goes out, then I wouldn't worry too much about the rabies shot. There isn't much of a way she can contract rabies unless you contract rabies and you bite her. It is highly unlikely that a rabid mouse or bat would get into your home and bite her.
The only other big worry would be if the authorities do a search and seizure of your home because she is not vaccinated.
Don't get me wrong, if she goes out any at all, by all means get that baby her shot. Maybe you can get someone to drive you and you could hold her on your lap.
good luck. hope all is well