have a browse around boredofstudies.org and download some notes. im sure they will be able to help you.
try this:
http://www.boredofstudies.org/view.php?course=6
theres not a lot though
it will also be useful to have a look at some websites like sparknotes for character analysis, plot summary, etc...
the bad thing about this text is that shakespeare didnt intend to write Antony and Cleo to demonstrate 'powerplay'. it was primarily a love story. and so, many antony and cleo references will not have references to 'powerplay' as such, although some will hint at it.
so, have a good look around. im sure ur teachers will be able to help you find some extra resources as well.