You cant and will need it re-done.
Unless youve got your own kit, which most of us dont have.
Reason being is that the one on the car is going to be different that the one youre going to fit. Ive tried, believe me- measuring, counting threads...the problem is having an accurate reference-point. Provided you do nyour best, make sure its free-turning and greased- a tyre place shouldnt rip you off. If your steering wheel is straight or was before you had the mishap- then you will know if its been done correctly.