Radio Frequency Identification (RFID) is a well known technology that has entered successfully in the realm of innumerable applications and is considered as one of the principal building blocks for the realization of the Internet of Things concept. However, the majority of RFID applications require the utilization of multiple RFID readers and therefore effective and efficient planning of their networks is a major concern. Network planning is a complex process that involves different steps, one of which is its topology design. In this paper, we focus on the topology design process of a RFID network following an optimization-based approach. More precisely, we propose a multi-objective cost function that is used to evaluate candidate solutions for the position and power levels of the set of RFID readers to be deployed. In order to obtain optimal solutions we applied Genetic Algorithms, a well known heuristic technique. Finally, a developed software tool to assist in the topology design is also presented and processing delay measurements are performed.