Molecular communication (MC) represents a promising approach that employs molecules for facilitating communication between nanomachines. The diffusion-based MC faces significant challenges in terms of communication range due to the attenuation of molecular signals. To address this issue, an intermediate nano-machine is utilized as a relay between the transmitting nanomachine and its intended receiving nano-machine. In this paper, we introduce the amplify-and-forward (AF) relaying method to enhance the communication distance and ensure reliable long-distance communication in diffusion-based MC systems. We examine the impact of relay position and reception radius on system performance, utilizing the minimum error probability (MEP) detection criterion for signal reception. The performance of the MC is significantly impacted by the reception process of the information molecules. Simulation results indicate that the relaying scheme can effectively deduce the bit error rate (BER) by up to 11 dB when a large number of molecules are released.