It's been more then 21 days since I have been accepted. I check on its.gov and the status of my return is still being processed. When can I expect my return to come?

Only the IRS will know what all they are doing with your return.

If the IRS "Where's My Refund" tool at  http://www.irs.gov/Refunds
shows that your Federal return has been processing longer than 21 days, you can phone the IRS to see if you can learn anything about the delay.

IRS:  800-829-1040  hours 7 AM - 7 PM local time Mon-Fri

Listen to each menu before making the selection.
 
First choose your language. Press 1 for English.

• Then do NOT choose the first choice re: "Refund", or it will send you to an automated phone line.
• Instead, press 2 for "personal income tax".
• Then press 1 for "form, tax history, or payment".  
• Then press 3 "for all other questions."
• Then press 2 "for all other questions."  It should then transfer you to an agent, but there is likely to be a long wait.