When i read the first two lines i was like "oh my god, someone is writing about me!!!"....
But thankfully as u went on i realised i wasn't that bad.
I sit here and do nothing, simply because i have nothing to do because its a tiny office of like 3 people. I wish i was busier but there's nothing i can do.
I think you should stop doing her work for her for starters and leave all mail on her desk. If you are waiting on a letter, simply ask her if any post has arrived for you.
I dont see how secretary's/administrators get away with "painting nails" etc... at least i look like im doing something at my desk!
If i were you i'd have a quiet word with ur boss and tell him/her that there are others in the office that feel the same way.
Anyway, good luck! x