How can i downgrade recently updated application on iphone 4S

I updated some aps on my 4S (e.g. YM, FB & Twitter) to the latest version designed to have support for IOS 6, all of them are reacting so slow and freezes sometimes. How can I get the older version of those aps? I wish I didnt update those aps. That's the reason why i dont want to upgrade my IOS 5.1 to IOS 6.