depending on which A13 you have.
If it's the short block variety(stroke:70mm), then the A12 crank will work just fine with no modification required.
If it's an american tall block variety(stroke:77mm) then you may have to play.

It shouldn't cost too much to get your crank ground and fit new bearings though, You already need new bearings, and a second hand crank may need grinding, or at least linnishing for the new bearings.