In this paper, we propose a beamforming algorithm for binaural hearing aids with enhanced noise suppression capability. The enhancement is based on incorporating a priori spatial information into the conventional multichannel Wiener filtering (MWF) approach for noise suppression. We develop a low complexity algorithm for the resulting quadratically constrained beamforming problem. Through numerical experiments, we demonstrate that the new algorithm can achieve better noise suppression performance than the existing beamforming algorithms under fairly realistic conditions. In addition, we propose two techniques to further reduce the algorithm's computational complexity and the communication overhead between two hearing aids without sacrificing the noise suppression performance.