I'm studying for the astb using the ARCO book and the pdf file highlighted on Navygouge.com. Are there any other books/sources that I should study? Does 2 weeks of study sound like enough?
Honestly, that pretty much entirely depends on how ready you are now and what kind of score you're shooting for.
If all you need to do is just work the rust off the math, verbal, and physics, you'll be fine.
Shouldn't take you more than a day to figure out a foolproof system for the spatial.
And the aviation/nautical stuff...it depends on how much you already know about stuff like that. Nothing rocket science, just a really broad spectrum of topics. You can get asked questions ranging from the in flight emergency transponder code to the properties of various weather conditions.
But obviously if any of that stuff scares you, then a 80 9/9/9 is out of the question.
Same goes for other sources to look at. If you're going to struggle with math or verbal, get a SAT/GRE prep book. For mechanical, I personally don't think it's time efficient in 2 weeks to bother with anything besides the gouge and the Arco. Arco is decent prep for spatial too. And wikipedia is probably going to be your best source for the aviation/nautical section.