Before revision:  We present an exact algorithm with O( k^{2 +  n^2\log n) runtime and O(kt^{2 , assuming that no three points lie on the same line.
After revision:  We present an exact algorithm with O( k^{2 + kt^2\log{n n^2\log n) runtime and O(kt^{2 , assuming that no three points lie on the same line.