There is an app called MTK Control which will let you set your data, WiFi and even the SIM off and on. It even has widget buttons so you don't have to open the app to change your settings. It integrates with Tasker as well (you might need some of their add ons as well if you want to do some extras)
My problem is that I can't seem to figure out how to automatically stop the background data usage while using the mobile data and turn it on again when I'm on WiFi.
So if you figure that one out, please let me know.
Hope that is of some help.