An Ad Hoc network consists of mobile hosts that can dynamically construct a wireless network without base stations. Due to the limited communication range, a source host usually needs other hosts to relay messages to the destination in a multi-hop manner. Consequently, establishing a routing path from the source to the destination is a basic requirement for providing communication service between any pair of mobile hosts. This study proposes a two-level management approach for efficiently constructing and maintaining a QoS routing path in Ad Hoc wireless networks, significantly reducing the quantity of control packets. In the first phase, the mobile hosts are partitioned into a number of complete graphs, each represented by a Supernode managed by an agent. The Ad Hoc network topology is thus transformed to an Agent-based Graph (AG). In the second phase, some agents of a larger degree than neighboring agents are selected as core nodes. The core nodes then virtually construct a Core Graph (CG). The proposed two-level hierarchical management and bandwidth-looking-ahead technologies can efficiently establish and maintain a QoS communication path at a low control packet cost. Simulation results indicate that the proposed management model significantly reduces the number of control packets in areas with very large numbers of mobile hosts.