Asp.Net Billing/Invoice software

Looking for the development of Asp.Net Billing/Invoice software with the following features: 1. Site where users can sign up to plan 2. Login to billing software 3. Create Products/Billing Items 4. Create Clients, adjust rates based on client 5. Employee login to submit billings for client project 6. Client login to view, print, pay invoices 7. Create Invoice, Packing Lists, Credit Memos, Purchase Orders 8. Multiple Billing types such as Expenses, Retainer 9. Filter/Track invoice 10. Configuration with email, international tax, late penalty, payment options (PayPal IPN etc) 11. Optional Inventory tracking 12. Multiple user accounts 13. Multiple Invoice/Thank You/Reminder, Mailing label Templates 14. Reoccurring billings 15. Print Invoices 16. Reporting/ Project invoice views 17. Backup System 18. Billing tasks - retrieve email from billing email account and notify admin and store copy of email in clients file 19. Develop an API and documentation for API for integration with other applications Note software must be in asp.net 1.1 and vb.net and use My SQL Server as the database. Software must work on IE, Safari, IE for the Mac, Firefox and most other common browsers. Looking for software similar to - [login to view URL] but without the store and warehouse features and in .net and some other adjustments Looking at timeline of 40 days for development and communication via Yahoo Messenger every few days. We will have an in depth specification within the next week Looking at budget of $600 for this Payment by GAF Escrow at project completion