Hi,
I can create this web application for you using PHP with a MySQL database for storing data, so you will be able to host it anywhere you want. There would be an agent section with all the requirements you specified and, if needed, a manager/admin section allowing global reports and overview.
I expect to have it completed within 7-10 days.
You would deposit half of the amount with Freelancer and release it once you receive the first working version of the application. I'll invoice you for the other half only after you're completely happy with every single detail :)
Please let me know if you have any questions :)
Take care,
Alex