1. How long does it take you to apologise in any situation?
Usually almost never, because I put my mistakes behind me and don't dwell upon them more than necessary to learn from them. People who expect an apology might as well dip themselves in hot oil, because I never apologize just because someone feels like they or another person deserves one, I have to feel as if I mean it or I won't say it, and saying/doing anything to force my hand usually has the opposite effect.
If someone I care enough about is hung up on something I did, badly enough, I'd apologize if I felt it'd help the situation any, and if I felt I could do so without sounding bitter, angry, negative, or insincere.
When I do apologize, it's usually within a day or two if I can.
2. Have you ever taken back an apology?
Never. Getting an apology from me is rare, and when I do say it, I always mean it.