Wireless Network Configuration Troubleshooting

Our office Wi-Fi has started acting up: devices drop off at random and new ones fail to obtain an IP address. From everything I can see, the problem is rooted in configuration errors somewhere between the access points, DHCP settings and firewall rules... (Budget: ₹1250 - ₹2500 INR, Jobs: Cisco, Computer Security, Network Administration, Network Engineering, System Admin, Wireless Network Risk Analysis & Reduction, Wireless Network Security Analysis, Wireless Site Survey)