Population
There are roughly one hundred worlds in the Romulan Empire. The worlds of the Empire include: ch'Rihan and Ch'Havran, Agurtha, Gaius, Hasdrubal, Hellaro Corva II, Justarus, Paxar IV, Pollar, Quatel, the Subera Penal Colony, Sudeka III, The Tareus Shipyards, Tegedaar, Tigelis VII, Zyqrna III, and Zyqrna IV.
As you can see from the maps above and below, The Romulan Empire is positioned between the United Federation of Planets and the Klingon Empire. The Homeworlds are roughly in the center of the Empire, orbiting the star Eisn. Having been stopped by the two rival governments in its coreward expansion, the Empire has turned its attention spinward. There are roughly Five Hundred Billion Sentients living in the Empire with another Fifty billion on frontier colony worlds such as Zyqrna III in the triangle.
Imperial Navy
The Imperial Navy currently contains some three hundred fifty D'Deridex Class A Warbirds, five hundred D'Deridex Class B Warbirds, four hundred and twenty five D'Deridex Class C Warbirds, four hundred five Scout Ships, six hundred four Science Vessels, three hundred eight Birds of Prey, two hundred and fifty six Battle Cruisers, seventy five T'Rasus Class light Starbirds, and thirty-two Starbases. The new designs, D'Kazanak Class Warbird, Advanced Bird of Prey, Advanced Battle Cruiser, Selok Class Bird of Prey, and Ostberg Class Dreadnought have not yet begun full scale production. The Talon Class Bird of Prey is being produced now, but is only for use by the Tal Shiar.