Auto-Post new CMS articles to Facebook or Twitter

[Merlok]

I am searching for a modification which automatically posts new CMS articles either on a Twitter account (which I specify) or on a Facebook Fanpage (which I specify).

The addon must not include both options (Twitter and Facebook together) but at least one of them.

I should be able to define a Twitter account or Facebook Site where to post new CMS articles from the admin panel.

Example:
An user is creating a new article in the CMS. When he published the article a notification is automatically sent either to Facebook or Twitter with a predefined account (from the admin panel).

I searched a long time now in this and other forums for a modification like this, but without success.
Does anyone knows a modification like this, or would develop a modification for me (I would pay for a working solution)?

Thanks in advance.