I would say; The government has better ideas about what is needed FOR society. An example of 'in society' is: Everyone has a role IN society. An example of 'to society' would be; Technology these days is very important TO society.

The correct and natural way to say this would be: The government knows best what is needed for our society. (That is if you are talking about your government.)

I'd say: Government has a better idea about society needs or Government has a better idea to what is needed for society