Labour Allocation, Productivity and Bonus Software

General information for the business: We are a construction contracting business that works on multiple sites in the UK with about 70 directly employed site staff
Kind of development: New program from scratch
Description of every module: The software we are looking to develop will replace a number of excel spreadsheets that we currently use. Our existing system is clunky and we end up doing things more than once.

Once final days worked and bonus is calculated this data will need to be exported to our current accounting package.

How the software functions and looks is very important it must sit within our brand guidelines and would like the look and feel and functionality of windows software.
Description of requirements/functionality: The software will need to have the following functions:
Management the weekly allocation of our 70 Site Operatives, where they are working, how much work they have done etc.
Manage the weekly productivity of all site staff, this information will be manually inputted from time sheets.
Calculate the bonus that needs to be paid to each operative on a weekly basis depending on what work they have completed.
Also reporting will be an important function so we can review productivity on a project and individual basis.
They system will also need to be able to produce pay reports for staff to show them what they have earnt and where. (This data is all before tax and before the data in transferred to our accounts package)
OS requirements: Windows, Mac OS
Extra notes: We have produced a technical spec for this software that will be available on request.
A key point to note is that we would require any software developed, will remain the property of our business.