Development and updating of existing PHP website - CodeIgniter - WordPress -- 3

Our company has an existing PHP website which we would like to have updated with new features. The site acts as a booking system with 4 different control panels, all with different permissions and roles within the site. It has a WordPress frontend; however the backend has been coded in PHP CodeIgniter. At the moment the site is hosted on a dedicated development server which uses a Plesk control panel. At the moment the site does not have the functionality to add different products and services. We would like to be able to do this. We would also like to improve the credit based payment system which is used for trade accounts. We want the ability to offer different types of trade account which will be determined via a monthly service fee. These accounts will have to be authorised before they can be made. Above are the biggest changes we are making to the system; however there are other smaller changes which will need to be made as well. A full document containing all of the changes in question can be supplied if asked for. We are looking for a development team who has a firm grasp of the PHP language. They also need to speak English to a good standard. We expect to liaise with the development team on a daily bases and expect daily reports of work that has been done