Wifi and 3G

[Aaapiie]

Hello,

I'm looking for an aplication to manage your data traffic
I'm about to get a subscription with 50 mb data.

So my point is that if I'm connected throught 3G I only want to use data for WhatsApp.
Not for Facebook or Twitter. (also not on the background)

I heard that in android 4.0 this automaticlly is build in. (but I have 2.3)

So who know's an app to manage these kind of things??

Greetz, Aaapiie