Keep your diplomats busy offering cease-fires and trade rights with the other Roman factions. They will normally agree after you spank their armies. With the offer always demand large sums of money. How much? Look under your "Faction Ranking Scroll" to see how much they have. Ask for it all. They will normally ask for one of their cities back, tell them no, and ask for a slightly smaller amount. You will have your requests granted (grudingly) from time to time. I normally go to war and then peace many times with the other factions, while I patiently plot where I will move my armies next. The key is to be victorious in battle - this improves your chances of diplomacy. Spend your money do not horde unless you want bad traits. And yes, you are doomed to be in a continual war/peace situation with the other roman factions. There can be only one winner, and they will always strive to retake Rome while grinding you under their bootheels. Never take your eyes off a known enemy, keep draining their treasuries and decimating their armies and the game will be over. On to the next faction/game. Try one of the barbarian factions next. More challenging.

Personally I never screw around with "changing files" to give myself an advantage. (This does not include "modding" for a specific flavor of game.) You will become a much better manager of finances, armies, and city management if you learn from doing. This includes making mistakes. This is what seperates the Total War series from the other games and why some will never be able to be successful with the game. Have confidence in yourself.