I just picked the first picture of a gear puller that I came across. The one you have linked to looks to be pretty much the same thing but you have to assemble the tool yourself, strange but there you go, I suppose the bonus is it packs neatly away in a box.
If your cranks are completely screwed then you may as well just cut them off and save the expense. Just saw a slot or maybe two in the crank where it joins the bb axle and tap off with a hammer and punch. Or are you concerned you might damage something else?