The first thing I wonder is, does she actually know what to do with all this stuff in an emergency? We might just take it for granted that everyone would automatically know what to do with duct tape and mason twine and cotton balls. But not everyone is a MacGyver, I think most people would look at this stuff like it's an alien lifeform. I'd actually simplify and give her just the basics. Even with all the best survival gear in the car, if she's not interested in learning how to use it, it's worthless.

For example, do you think she'll know what to do with mason twine or PJ soaked cotton balls? I know my girlfriend wouldn't. Does she know how to use jumper cables? It's funny how many people don't know how to hook them up properly. I actually had to help a couple of people who were trying to jumpstart a car, they had the cables, but didn't know how to hook them up. Tool sets are useless if she doesn't know how use them to fix a car. Same with a huge first aid kit. Unless she knows what to do with all the stuff, anything more extensive than bandaids and bandages might just go to waste.

For a basic kit that won't overwhelm her, maybe start out with some simple things:

Bottled Water
Snacks
Warm Clothes
Gloves
Fix a flat
Portable Jumpstarter (Not the kind that plugs into a cigarette lighter, but the kind that hooks directly to the battery)
A good cell phone
A multitool
Lighter
Simple first Aid kit
Money, credit card, or phone card

And then slowly add to the items one by one as you teach her how to use these things.