How can you get back some money that the dealership unfairly took in kind if not in cash?

I bought a 2007 328xi with 73, 230 miles from a dealership in NC on Aug 7 2014.( a
BMW dealership). The car had "active steering" on top of the hydraulics of that time. I
wasn't told. Extreme effort was needed to turn the steering in slow turns and reverses,
that in 2 months I ended up with right shoulder joint pain. I took it back 67 days from
date of purchase with ONLY 1300 miles on it ( I am studying for my dental boards and
so only go to groceries, and library near my home) and they only gave me $11K back
for it.  Had bought warranty and everything, not one ding or ANYTHING! They had
charged me $15500.00 2 months back on Aug 7, 2014 for the same car. I feel that
they shortchanged me and I would like some money back. I already bought another
BMW 328xi of year 2011 from them.  Is there anyway I can at least have maintenance
package thrown in for 2 more years? The 2011 car already has 1.5 yrs of maintenance
package and up-to 4 years 60K miles warranty given with the car.