Booking module mods

HI, I need a small modification to my booking module written in php. I need to add an option to select a different room for rent in a holiday apartment, and I need a drop-down menu on the actual page where a client makes the booking. MySQL database will need to have the room field and the price field for that particular room added to the table. Once this is done, the changes need to be integrated into their respective pages on the site. Also, I need all fields in the admin module released so that an admin can fill them in or leave them blank as they wish. Currently the fields are mostly mandatory fields. My estimate for the php/sqlpart is 12 hours of work. I have included 2 hours of familiarisation with the module in my estimate. I am willing to listen to good arguments if you are an expert. I expect us to discuss everything in detail before you start and I will provide screenshots to help you visualise the task. You will need to add the items to html5 page, so if you do not know how to handle it, please do not bid.I am looking for a clean and neat product. I know the code inside out, so please think about your estimates and suggestions. Matt