Simple Paypal invoicing system

Hi there, We are looking for someone who can develop us a system where we want these things : 1. Shall work from an IP and should be integrated with Paypal API. 2. Separate login for both admin and agents. 3. Admin / Agents can create invoices, invoice should have a discount option (if user provides any code, agent will put that code and generate invoice). It should show on the invoice. Like (Coupon Code : CODE HERE Applied). 4. only admin can create coupons. 5. once the invoice is generated, it should give a payment link which we can provide to the customer so send it on his email. 6. once the payment successful / unsuccessful it should redirect to the website with success or error message. 7. admin should be able to view all the transaction details, successful or declined. 8. must have filters for payments month wise, date wise. (optional if u can add PDF or excel download) 9. passwords must be MD5 or higher encryption looking forward for your responses.