After much consideration, I'd recommend throwing everything we have at the Roman capital. The one weakness of our Peltasts is that they lack a hp compared to many of the units they are fighting. This means we need vets badly. Rome has a wonder that gives all cities barracks (we cannot build barracks, so this is doubly important).
We have a healthy army, that you can use as cover to build a city on the tile SE of the wines near Rome. Once both armies are healthy, you can park them and about 10 vet/heroic pelts right next to Rome. This should be sufficient to take it out (estimating 6-8 defenders at this point). After that, we can build vet pelts in all our cities, and should soon have Mapmaking, which will allow our amphibious pelts to dominate the Mediterranean. With our seafaring trait, our economy should then take off.
Until we get Rome, I'd recommend using our GA to build mostly infra, as reg pelts are pretty fragile, and there won't be many more easy promotion opportunities.