Sensor placement in a wireless sensor network, that consists of a number of target points, determines number and locations of sensors required to cover the points. In this paper, we define a sensor placement problem called HPC to cover a large number of target points with various coverage requirements using a minimal number of sensors. We divide this problem into sub-problems and then design an algorithm for finding an approximate solution to this problem. Also, we develop a software tool containing the implementation of our algorithm that graphically displays network model and placement. Our evaluation experiments show the performance of the proposed algorithm.