Requirements for Rome Total War 2 are 2GHz Dual Core Intel CPU, 512MB VRAM, and 2GB RAM, so yes, that spec should run it no problem. The only real issue will be running a game that old if you're using a modern OS.
Many are having problems running any Rome Total War games on W10, but if it's a Steam copy, this thread may help. Read the suggestion in the 2nd to last post. One person said it worked for them.
https://steamcommunity.com/app/214950/discussions/0/523898291513448452
As far as a GPU for that rig, I'd say a GTX 1050. The CPU may hold it back a bit on some games, but it's only $140 for one with decent cooling, and performs on par with the 760, which was one of the best value GPUs of it's time...