Create Reporting-E-Mail from Infos via API (XML / JSON)

Fastbill is a time tracking and invoice generating tool. I need a website (I dont care how - even a WordPress Plugin would work) where I (and others, so I can use it as a SAAS) can log in, add my API-Key, see all my clients and active a reporting. In the reporting email, is the list of things I have done this week/month/day. And at the bottom also the sum of the hours that have not been billed yet. Here is the information about the api: [login to view URL] Any suggestions on this project, to make it easy, are highly appreciated. I am a designer, so I can do the webdesign part of this. But I can also imagine to work with some kind of admin-template for a few dollars from ThemeForrest for example. Everything to finish this thing as soon as possible. Oh: I need to be able to translate the language into german, so there has to be some kind of language file I can work with. Thanks!