Forgot to include 1042S when Filing Taxes

I had just filed my Taxes using the W2 forms but then I realized that I had forgotten to include the scholarship amounts I received and details from the 1042S form. I believe this would lead to me receiving a larger Tax Refund. 

 

I would deeply appreciate any assistance on the matter and steps towards amending the mistake. I also hope I would be able to amend the error past the filing deadline.