I use my entire hand, just like I was taught at school. When I'm about to type anything, my hands just instinctively go on the entire keyboard.
Typing I'm sort of in between fast and slow, around 35 to 45 (the faster the more mistakes I make) words a minute. I do tend to make lots of spelling mistakes (not just punctuation, but certain words too), so in PC I tend to use the edit button a lot.
edit: I just remember, the only time I use two fingers is when I need to use an ALT-character and don't want to bother switching between languages, especially between English and Spanish.