This paper proposes a new approach for reducing average call delivery cost and location server's load of wireless mobile networks. It uses caches whose up-todate information is responsible for dropping these costs and these caches are updated not only during call arrival moment from the calling mobile hosts (MHs) but also during call receiving moment to those MHs. To achieve load balancing among replicated home location registers (HLRs), hashing technique is also used and this load is also affected by up-to-date cache information. The analytical model and experimental results show that our proposed method prepares the cache with up-to-date information more frequently with the increase of average call arrival rate as well as average call receiving rate. This increases probability of finding MH's location as well as hit ratio of the cache. As a result, both the average call delivery cost and load on a particular HLR are minimized considerably than all other previous approaches.