Urgent !!!! Magento Module Development

Need a module to magento for integration with a economic system. The module should create the user and then order/invoice in the economic system and also mark it paid in Magento when its paid in the economic system. When the user is updated in Magento or the economic system it should be updated in the other system. This project is urgent and the coders must be able to write in english on skype/here for any questions. Provided is the API for the economic system. The API is based on the JSON-RPC/HTTPS protocol. Username and passwords to testinstallation is provided when the coders is choosen.