Holy SCHAMOLEY. 40 mins?
I'm surprised that the whites weren't like rubber tires. Yeah, 40 mins is waaaaaayyyyy too long to boil eggs. A hard boiled egg shouldn't actually be *boiled*. Here's the best way to make them:
Put the eggs in cold water over high heat. Bring the water *just* to a boil. Turn off the heat, cover, and let cook in the hot water for 17 minutes (20 mins if you're using jumbo eggs). AT the end of the cooking time, remove them from the water and immediately cover them in ice water. While they're iced down, crack the shells all over ... the water will get between the membrane and the egg and make them easier to peel.
I don't think a week is all that long. I routinely boil a dozen eggs on Sunday night and eat them throughout the week. By the next Sunday, I"m ready to boil another dozen.
The green tinge to the yolks is caused by a reaction between the iron in the yolks and the sulfur in the whites when the egg is overcooked. It's not bad for you .. it just looks funny.