Hyundai Repair: Check Engine Light, hyundai xg300, oxygen sensor

Question
I am driving Hyundai XG300 model 2001. Recently some one hit my car in parking lot in front side. The front bumper came out with some wires but I was able to drive my car to the collision center and than to Body shop.The body shop fix my front bumper and when I start my car to check things before taking the delivery form body shop, I found my dash board show the battery and Brake lights on. I asked the body shop and I was told that this is because of the low battery and the lights will go as you drive you car for couple of kilometers. I took my car and while driving for few kilometer I got a jerk in the car like I lost power for a fraction of second and I got my check engine lights on addition to the two other light on for battery and brake.I took my car back to body shop and After going through the test they told me to replace the Alternator and the Map sensor which I replaced and after few days I got the same type of jerk in the car and again I got my Check Engine lights on. I took my car to the body shop and they told me that my oxygen sensor might ( they were not sure ) be gone. Than I show my car to other mechanic and after checking he told me that it has the problem of Injector and he suggested me to use Injector Cleaner with fuel.I started using that and my car was running excellent and the Engine Check light was gone. since few days again my check light is coming and  going often. Be fore my check engine lights come I observed my steering wheel will become hard and not as free as it used to be than other experience is my car will slow down and it will not respond on my pressing gas pedal and than it will give a jerk and I feel like something is free form choking and than I will have my check engine lights on and car will again run smoothly. Once again I took it to mechanic and after checking he show me on the meter and told me that my speed sensor has gone.I am really confused because lot of money has been spent but still my car is not free from problem. Can you please give me some advise what could be wrong in my car. I am sorry to write a long story but I wants to give complete information of the problem of my car. Thank you very much and have a nice day.

Answer
The alternator diagnosis sounds correct.  And the later symptoms you describe could be caused by a transmission input or output speed sensor.  I can get a better idea as to whether this is the issue if you can give me the diagnostic trouble codes.  Neither of these would typically be related to collision damage.

As for the steering, you'll want to be sure the power steering fluid is at the proper level, there are no power steering leaks, and that the lines haven't been pinched or restricted by the collision.