Need a download manager for magento 1.7

Hello, I am running a magento CE 1.7 store and I sell downloadable contents (software) whose file sizes are pretty big (from MBs to GBs). Currently, the user needs to download and collect his license number by clicking the link from MY ACCOUNT section. I want you to make a download manager application for my store. When the user starts the application, he will need to log in to the application with the same login details as in the main store. After he logs in, he will see the list of software that has has purchased. There will be a download button beside the name of the software. When the user clicks on it, the application will start downloading automatically. Products not yet downloaded will say as "DOWNLOAD NOW" Already downloaded products will say as "DOWNLOADED" Beside the download button, there will be a button that says "CLICK HERE TO VIEW THE LICENSE CODE" User can pause download, resume download, cancel download and select the number of downloads that can run simultaneous. We need this application to be multi-platform. We need an installer for PC and also for Mac. Some more features will be required but this is the main backbone. More details will be discussed only with the selected bidders. The source codes, raw files and all the rights must be submitted to me.