...worst case scenario, if the crankarm is toast you can always put a new one on (they are available).

Well, unfortunately this isn't the case, which is why I am so upset/worried. The crankarm and the big chain ring are attached; one shiny, beautiful piece. It is exactly like the one in the image. So, if I scrap the crankarm, I lost a perfectly functional chainring with 1000's of kms left on it. Sigh. Is a re-threading possible without the helicoil kit, or will the diameter of the newly bored hole be too big?