How long until we can build R2-D2 and C-3PO?

Well, we can build them now, just about ... but can they socially interact?

The Star Wars universe is full of droids. Everywhere you turn, there are medical droids, exploration droids, labour droids, pilot droids, even battle droids. They carry out clearly defined tasks, often with a degree of independence, without needing to interact with people."