What happened to Marie's Antoinette family after the monarchy was overtrown?

Well, she didn't have a lot of family left. Her husband was killed 9 months before she got beheaded herself, and her children:

• Marie Thèrése (20 December 1778 - october 1851)
• Lodewijk Jozef (22 october 1781 - 4 June 1789)
• Lodewijk Karel (27 march 1785 - 8 June 1795)
• Sophie Beatrix Hélène (9 July 1786 - 19 June 1787)

As you can see, the only Survivor of the revolution was Marie Therese, her firstborn daughter.