What you should do is stop talking and focus more on showing. You know why your girlfriend’s father isn’t forgiving. Not only did you key the car, buy you did so while intoxicated. From his point of view, you are not man enough for his little girl.
It was a huge step in the right direction to apologize and to pay for the damage. But how is he to know that you won’t do the same kind of stupid thing if you and his daughter have another falling out?
Instead of calling him names and making excuses for your own stubbornness, show him that you have learned from the experience and are mature enough to be worth his time and his daughter’s love. I hope you are doing well in school or in a job. I hope you learned that partying at the level you were that night doesn’t do anything positive for your reputation with your girlfriend’s family — or any other mature adult for that matter.
Don’t ask your girlfriend to be in the middle by criticizing her father. Choose compassion for his position instead of anger that he doesn’t come around as fast as you would like him to.
I wish you well.