hi Laundry,
how is the pin broken inside?
Do you mean that the pin on socket on your notebook has came off and is attached to the plug on the adapter? If so, you will need to replace the socket in your notebook. It will require soldering.
If its under warranty, please do go back to the agent. But if the warranty has expired, you can try your luck at sim lim. If you want to DIY, open up and find the part you need to replace and try to find it from Sim Lim Tower.
But if what you mean is that the adapter is broken with part of it in your notebook, all you need is a pincer to carefully remove it. Then, you can quite easily find a matching replacement plug for the adaptor.