An architecture introducing wireless relaying technologies into the cellular infrastructure has emerged as an approach to enlarge the coverage area and enhance system capacity. In this paper, a two-hop cellular system incorporated with the fixed Relaying Station (RS) is studied, where besides the Uniform Power Allocation (UPA), the Optimal Power Allocation (OPA) between the Base Station (BS) and RS is also adopted considering resource utilization. To maximize the performance gains and reduce the overhead, it is necessary to provide an effective RS selection algorithm and combine it with other resource management strategies. So two kinds of RS selection criteria based upon Signal to Interference Ratio (SIR) and PathLoss (PL), are evolved into four Joint RS Selection and Power Allocation (JRSPA) algorithms, which are based on SIR with OPA (SIR-OPA), SIR with UPA (SIR-UPA), PL with OPA (PL-OPA) and PL with UPA (PL-UPA). The simulation results show that among these four algorithms, the SIR-OPA scheme provides the best capacity performance, but taking the overhead into account, the PL-OPA scheme is a better choice to reduce the complexity and trade off the system performance with signaling load.