Wordpress Customization with Plugin

witty templates offers memberships to download website templates and sofware. Right now, all templates are only available by zip files and are very hard to look at for users. I would like to offer functionality using wordpress and the plugin "download manager" to act similar to themeforest.net. I know all of the functionality is already included in the download manager plugin, I just need it implimented into the wordpress site. I also need to offer the download link only to members (which download manager supports with a checkbox). If there is a plugin or something to allow users to pay using paypal for a membership, then get a member login that would be ideal. The members and non-members should see all of the same products only the members will have a download link. i do not need any design work done other than the download layout and sidebar layout. i will provide dropdown menu for the sorting, i just need you to provide me with the functionality and URL's to use. i do not need you to upload all of my templates, just a few for samples. downloads will include, thumbnail image, html layout for preview and download link. I have the site setup with categories and have download manager installed - [login to view URL] ## Deliverables PLEASE LOOK AT ATTACHED SCREENSHOTS FOR FUNCTIONALITY AND DESIGN REQUIREMENTS.