In this paper, we evaluate the performance of a dual-hop fixed-gain amplify-and-forward (AF) relay system in the presence of co-channel interference (CCI) at the destination. The analysis assumes a noise-limited relay and an interference-limited destination. Furthermore, the source-relay and the relay-destination channels of the desired user are assumed to be Nakagami-m distributed and the interferers' channels are assumed to follow the Rician distribution. We derive approximate closed-form expressions for the outage probability and the average symbol error rate (SER) for the proposed system. Both, the independent non-identical distributed (i.n.d.) and the independent identical distributed (i.i.d.) cases of desired user channels are provided. The Monte Carlo simulations are provided to validate the accuracy of the analytical results. Also, the impact of the interference and other system parameters, such as the fading parameter m and outage probability threshold on the system performance are considered.