Develop a online hotel booking system for current HTML site

I need to add a easy manage hotel booking systems to 2 of my current HTML site. I believe we need to build a MySQL databae. We need some back-end platform that is very easy to manage, as our daily staff would not have any website coding skills. The system has to be easy enough to manage. We want a system exactly to this page website: [login to view URL] Please give me your best suggestion of how we can achieve this. Please also show me some of your similar previous work. We only need the booking system to be developed. NO NEED to develop the whole website. If you have any other questions, please ask. We need this project to be done within 2 weeks. Our budget is $300.