Elgg fits your need. However you must be aware that elgg is not a finished product. A lot of coding and customization has to be done to get a great product.

Rodolfo Hernandez

Arvixe/Elgg Community Liaison

thank you guys. Do you have some devs to suggest us? We need kind of tech advicer to better understand the power of Elgg.

@Marux there might be a language barrier in your question but you can find documentation here 
http://elgg.org/developers.php