If you do make the animation in AE, you can loop any keyframed property, like rotation with this loop expression. Alt click the stopwatch of the property with the keyframes (rotation) and the paste in this expression:
loopOut(“cycle”, 0)
Note, the original layer must be long enough to handle all the resulting loops you want to happen. The animation will now loop as long s the layer is.
If you’ve created an animation that is just one cycle and the layer is just that one cycle long, render it out as Uncompressed or as QT Animation Codec at 100 (so you don’t lose quality), then re-import the rendered mov and when you bring it in, at the bottom of the interpret footage Dialogue Box, put in the number of times you want it to loop. If you don’t get that box when you re-Import, then select the footage (your rendered mov) in the Project Window, right click> Interpret Footage>Main (or Ctrl F) and put in the number of loops you want (at the bottom under “Other Options”). The footage will now be longer, enough to loops as many times as you put in.
Is this what you’re trying to do?