Oscillation problem?

Consider a 4.18-kg m on the end of a linear spring in simple harmonic motion. The spring has spring constant 9.5 N/m. When the spring is maximally extended, it is 0.0436 m from the place in the oscillation where it is maximally compressed. The equilibrium position of the spring is midway between these two extremes. What is the maximum speed that the m achieves in this oscillation? (Answer in m/s.)