Learn English – When a phrase ends with a period, do you put … or .. after it

The correct form of your example:

It’s all about apples, oranges, bananas, etc.

Jack Lynch’s Guide to Grammar and Style states:

This one is simple enough: never double up periods. If a statement ends with “etc.” the period in the abbreviation does double duty, serving as the full stop to end the sentence. If, however, you need another mark of punctuation after an abbreviation, you can put it after the period. So:

• This was her first trip to the U.S.
  (The period does double-duty, ending both the abbreviation and the sentence.)
• Is this your first trip to the U.S.?
  (The period ends the abbreviation, but the question mark ends the sentence.)
• On her first trip to the U.S., Kristina lost her passport.
  (The period ends the abbreviation, but the sentence keeps going after the comma.)

The only thing to remember: don't double the periods. Everything else is logical enough.

The only thing you have to "relearn" is that a full-stop at the end of reported speech becomes a comma when the sense runs on into the sentence which reports it.

"I'm done," she said.

That's one complete sentence reporting some speech.

It doesn't matter if what is being reported has its own sentence structure: that's contained within the quotation. It's the comma at the end which links the quotation to the reporting. Please be reassured that your example is correct:

"I can't take her. I'm done," she said.

Where you're reporting a trailing-off of speech, or some other ending, the punctuation mark isn't a full-stop so it doesn't become a comma. However, because the sense runs on into the reporting clause, that doesn't get a capital letter, in much the same way as the first example.

"But I thought he was..." he complained, lapsing into silence.
"Oh sh—" he whispered, seeing the car hurtle towards him.
"No!" she exclaimed, slamming the book shut.

Where an interjection interrupts the reported speech, I'd use a dash. There's no punctuation at all at the end of the first fragment, because there's nothing there in what's actually being said.

"I just can't" — she sobbed ostentatiously — "take any more!"