Def goto to an old skool enthusiast - a car dealer prob wont have a clue.
We have a guy/place called 'Lammos motorcycles' here - he has his family working for him now and they have all grown up looking after bikes and atv's - its bloody ace just to take a problem to them as they seem to have the knowledge of every conceivable mode of transport going - I dont know how they know what make/model it is but they always seem to order the right part for me.
Steering on a quad is not that hard or expensive to fix - maybe its best to drive it within its ability? I have a few vehicles that dont turn with half a turn of the steering wheel as various bushes, cotter or bearing are worn. Just drive the vehicle till it falls apart
(only make sure your not going fast when it does go!!!)