If you're just a authorized user on the credit card, you have no power to change the spending limit or cancel the card. However, I'm not certain if it's on your credit report. If it is, have yourself removed as an authorized user, so you can't be held liable for it.
Next, Google your city's court records and look up her name. Then show her that her bad record is public knowledge. Ask her if she really wants that out there for the elders or possible converts to see. Don't worry about her not graduating on time, because she can get driving privileges for necessary business like work and school. But ask her if she really wants to have to put the Kingdom Hall's address on the form and provide such a bad witness. Also ask her how it will look if she can't drive in field service.
If you're a registered owner of the car she drives, take your name off asap, and do not allow her to drive your car that is in your name under any circumstances. If you have car insurance for both of you, cancel it and carry your own policy. Otherwise her carelessness is going to cost you money in higher premiums. If you ever buy a house together, (which is doubtful since she likes to run up credit card bills), insist that she carry higher amounts of insurance to protect your home from law suits caused by her poor driving.
Insist on her paying her fines and for her own car insurance plus whatever she contributes to bills and expenses. I would also close out any joint bank or credit accounts you have. That way you can protect yourself now and in the case of divorce. Then simply refuse to take the Disney vacation. If she wants to go on her own dime, (or more than likely credit), let her. Just don't be the sucker who pays for her carelessness and thoughtlessness.
I know all of this sounds tough, but if you separate your finances and insurance protection, maybe she'll change her ways. If not, at least you won't be responsible for her poor decisions.