Develop a custom database web application in Drupal 7

We need to develop a customized web portal by Drupal and MySql. The application will handle a daily work for a company working in Recruitment (importing workers to their country). Handling visa requests for number of workers assigned for this visa and the contract between the company and the customer (which his need workers for their manufacturer). Then the company communicate with their agents around world and request workers by nationality or by age etc.. And assign each selected works to the Visa number and create their contract. The company need to organize daily base work and knows how much they gain money. And know how many workers pending in the process. Have a look to the attached file to know some idea on this application. I will provide: - Hosting with installed default Drupal site. - And Full analysis for the entire project to be able to work as fast and without any problem, and to get an idea how the system will work.