Web based reservation system

I have a reservation system that needs updating. I'm looking to start with a basic web based application that includes an editable grid with 5 Coloumns by default, but ability to add additional columns if need be dynamically. The first coloumn is the time of the reservation. The next four include up to four people for the reservation. if the person clicks add coloumn, it should populate another coloumn just for that day. Each coloumn should be editable to the person can just click and add or change the name that's in there. There should be a settings page that has these options that are used by default: number of reservation spots per time (grid columns), start time for day, end time for day, time between reservations. The grid (i've included a picture of what it may look like) will also have a nice calendar for changing days easy. When a day is clicked that isn't in the database yet, use the settings above to create the day. I have a reservation database that already has these fields. I will provide that script for creating the database. to place a reservation, the person should either right click or double click to add or edit the time. They should be able to select more then one coloumn and row at a time to make a reservation for any number of sequential times at once. When they add a time or edit one, it should bring up a lightbox with reservation information. The following items should be stored for the reservation: first Name, last name, phone number, email address, comments. Also, the database can be updated by multiple people so when you start a reservation, it should hold those times for 3 minutes (so no one else can book taht at the same time) or until the person either submits the reservation or clicks cancel. When on the grid, it should look to see if the database has changed by another user and update the grid every so often or as soon as a new reservation is detected. If project is completed on time and done well, I will be updating this for more advanced features in the weeks to come.