Once the update is released, you should be able to create pistons on your old worlds, as long as you can gather the materials. I'm pretty positive that pistons and sticky pistons were added in the same update, so they both should be added.
The upcoming update will include both pistons and sticky pistons. And you probably wont have to start a new world to get them. They will probably just be added to the crafting table.
Buckethead is the best guitarist ever. \m/