Adaptive Equipment problems of the 2002 Chevrolet Impala

I was driving staraight doing 40 and and I saw a vechile spend out of control I tried to drive faster to get out of the way but doing in the middle of driving the key falls out of the ignition causing the the other car to hit mines in the rear right no one was hurt but my car was scatch and a dent I notice it frequently that when driving the key comes out by itself its really scary and dangerous.

Shortly after purchasing this vehicle, I parked and when I tried to start it would not start. After waiting about 20 minutes it did start. I took it to the dealer and was told it was a sensor which they replaced. Did not stop the problem, continues to do it today. Now at about 8500 miles a message comes up to service tract system. Am told it is a sensor in the hub and the entire hub will have to be replaced at a cost of about $750 per hub for the front and slightly more if it is the rear hub. After reading on the internet of this same problem people are having, I realize I am not the only one having this problem and it seems all these fixes do not stop the problem. I purchase the car new and love the ride and performance I get from this car but am not able at the time to pay for expenses of this magnitude. Have considered trading but do not want to saddle someone else with this problem. Would not mind the repairs if it was going to fix the problem, but seems as if this is a problem that cannot be fixed. Help.