Dang? Where u roleplaing or something, sh*t 240BC and ur still in Italy.
This makes the game so much mroe fun, because your enemies are actually strong by the time you reach them.

Alright, what I would suggest at this point would be to empty the Patavium garrison of anyone that can be spared. It doesn't look seriously threatened, so lower the taxes and empty the people out of there. Start recruiting lots of Roman core units. Start playing around with having Gauls on your flanks. Their spears will work well against cavalry, and they will save you money.

Start getting some mercenaries and stuff ready in Bononia and Arretium. With these units and any other troops you ahve recruited by then, attack Segesta. This should definitely be enough.

Assuming Mediolanium holds (Which it may or may not), start placing your armies in areas that you can ambush people on their way to your towns. Also block off at least one pass with a strong garrison in a fort.

Then you should strike north with two decent strength armies (at least 12 or so units) and capture and burn Aventicos and Veldideno, letting them rebel. This should buy you some time. With this time, start recruiting more soldiers and mercs. Then you should strike at Massalia, which thanks to the bridges is very easy to defend with a medium sized army.

From there you could really go anywhere. I would ignore the suggestion to go to Spain, openning another front isn't a great idea at this point. Working your way along the south of Gaul would be alright, because you are taking the most profitable Arverni towns from them.

Anyway, that's my advice, take what you want.