I would like to add a specific table or shape file to my TOC via the ArcMap python window from the SDE connection I'm currently connected to. Since I'm already connected to the SDE connection in ArcMap I'm assuming I don't have to restate the user name and password in the python script right? How would I going about doing this?
Welcome to the site! You should check out the faq for info on how to best get your questions answered. Searching for keywords related to your question before asking might point you to the answer you're looking for.
On to your question:
If you set your workspace to your SDE connection file you can access features within. This post covers the process well.