Optimize VPS Windows web Server with MySQL Performance improvement

My Windows-based VPS is running a busy web application backed by MySQL, and users are starting to complain about slow page loads and the occasional bout of downtime that lasts a few minutes before the service recovers on its own... (Budget: ₹1500 - ₹12500 INR, Jobs: IIS, Linux, MySQL, Performance Tuning, PHP, System Admin, VPS, Windows Server)