Optimize & Extend PHP ERP

Our in-house PHP-based ERP has grown fast, and two areas now limit us: reporting and the user-permission layer. Both modules place a heavy load on the server, so I need them re-engineered to cut resource usage and scale smoothly as concurrent traffic rises... (Budget: $250 - $750 USD, Jobs: Apache, Git, JavaScript, JMeter, MySQL, PHP, SQL, XML)