Judging by your size that is a fair attack, Your units are good, I would recommend not using swordsmen for an attack, To take a city over get your academy to level 28 and research conquest and Colony Ship, then get your harbour to level 20, A great attack force is 600 slingers 230 horsemen 60 lightships and 80 fast transport ships with bunks researched, for your first city build 600 swordsmen 200 archers 500 hoplites 75 biremes and about 55 fast transports and 1 colony ship, that way you don't risk loosing a city as it has a very strong defence.