Niiiiiice, a noble challenge! that's exactly where I am! OK, Let's get down to it.
Your stack is a bit small, but I guess with upgrades it should be fine. If you are going to use elephants to storm alexander, remember he's got phalanx! They can take down unpromoted knights! It's happened to me! Also, if Augustus founded Confuciansim, convert ASAP. The last thing you want are praetorians in your land while your army is miles away. Augustus is also #2 in terms of points, so he's about the same technologically as you, so watch that. You also seem to have good land; why go conquering if your economy isn't up? Could you also summarize in your next post the wonder situation and what king of ecnomy you're using. Thanks and good luck!