Definitely. If you already filed your return and you got this W-2 afterwards, you gotta wait until your original return is complete before you file an amended return.
Also, amended returns CANNOT be E-Filed. It has to be mailed in, I believe to Kansas City, Missouri. So, wait until you have 3 bars on Where's my Refund, and then file the amended return. But to answer your initial question, you absolutely need to amend and include that new W-2.