I'm sorry for your loss!
The income your mother received after her death belongs to her estate and should be reported on the estate tax return (if the estate had $600 or more gross income).
But don't worry about double taxation! Estates are "pass-through entities" -- a special business structure that is used to avoid double taxation. Pass-through entities don't pay income taxes at the "company" level. Instead, income and deductions are allocated among the beneficiaries and income taxes are only paid at the individual beneficiary's level.
For an estate return (1041) you will need TurboTax Business. You can visit the following link to purchase the program: TurboTax Business.
TurboTax will take you through an interview to prepare the business return, similar to the personal (1040) products.
As part of preparing the 1041 return, TurboTax will prepare K-1 forms for each beneficiary, which they need to enter into personal 1040 returns.
