About a month ago my girlfriend decided to give me a frame(it says American Flyer on the front, not really familiar), she and her dad completely took it apart before she gave it to me. This was a mistake, I believe. Mainly because I'm really confused about the bottom bracket stuff, as I am new to bike mechanics.
I've learned alot in the past few days, but i'm still not entirely sure what I need.
You might want to try the bottom bracket measurement again. 70mm is usually an Italian threaded bottom bracket, highly unlikely on a bike badged "American Flyer".
Seems there's a new company using the American Flyer name, but it used to be a Schwinn brand based on a limited Google search. If that's the case, then you'll have pretty limited options for bottom bracket/crankset. Check this Sheldon article. http://www.sheldonbrown.com/opc.html