Suggest that you read IRS Pub 559 (Survivors, Executors, and Administrators) for a lot of good information about filing the final return and estate return and other requirements.

https://www.irs.gov/pub/irs-pdf/p559.pdf

You will not need to file a Power of Attorney for the income tax filing.  Instead, you will need to complete the following to establish your relationship as the administrator of her affairs.

When filing your federal return, you will need to do the following to ensure the return is filed for someone who has passed away.

1. IRS Form 1310 - Statement of Person Claiming a Refund Due a Deceased Taxpayer - This form can be completed within TurboTax if you have not already filed it.  
2. IRS Form 56 - Notice Concerning Fiduciary Relationship - This form will need to be completed by you to establish your relationship to the taxpayer.  It essentially allows you to file all returns as if you are the taxpayer.  Form 56 instructions

Form 56 will need to be mailed to the IRS center where your mom's tax returns are filed.  It is not prepared within TurboTax. Please see the following link for the address to use to mail Form 56.

Mailing addresses for IRS

For New Jersey, you do not need any other forms.  You will need to sign the return as a personal representative.  Please see the attached link for more details from New Jersey.

New Jersey filing for a decedent

Estate & Inheritance tax requirements if applicable - New Jersey

If you have not already, go to Turbotax.com to start her income tax return.  Be sure you have all of her information and follow the prompts as it pertains to her.  You will need to establish a new username and password for her account to keep it separate from your tax return.

As you enter her information, TurboTax will ask you if you had certain sources of income.  Based upon your answers, it will complete the forms or let you know if you need to upgrade if additional forms are needed.

Please note you will only be preparing her income tax return for income earned up to her date of death.  Any income earned after that, if any, would be reported on a trust tax return.

When you proceed through the My Info section of the program, be sure to select that you are preparing the tax return for someone who has passed away under Section 3, A few other things we need to know.

I'm so sorry for your loss.

First I would like to thank you for your detailed response.  It was a lot of help. 

I do have a couple questions if I may.

-  In filling out IRS Form 56, in Part I (Identification Section) the "Decedent social number" is of course my mom's social security number.  What about the second field called "Identifying Number"?  Is it my mom's social security number again?

-  In your section number 3 "A few other things we need to know".  The third item "I'm preparing this return for Jack who has passed away."  I believe the answer should be "Yes". 

Thanks again for your excellent support.

Solar7782

Glad I could help!  

The identifying number will be your Social Security Number as you are acting on your mom's behalf.  Otherwise it will be either an ITIN or EIN as provided in the instructions below.

And yes, that was just a sample of what the input screen looks like.  You are correct, you will answer as yes.

your power of attorney expired on death.

As personal representative, or executor, you have more powers above what was granted by the POA document..