"extended 1930's semi" - same here actually, and I get great performance from any 802.11G router that I have used here. It is placement that really matters - which is something that quite a lot of newbies get wrong. If you sit with a solid wall (or two) between you and the router, it is likely to provide less performance (how much less is open to many factors, of course) than if you were to sit above or below the router with only a floor and ceiling in the way. My router is diagonally above me right now and I can't fault its throughput. If I move into the front room, it's a little bit slower, but only to a point that affects file transfers - it is not slow enough to throttle an 8Mbit internet connection and it is still reliable.
Pre-n and Draft-n products will usually give greater speed (for file transfers at least) in good conditions, MAY improve reliability and speed in iffy conditions, but still won't do a great deal for anyone living in a Georgian mansion! It's all just very-high-frequency shortwave radio signals, after all.
Try a standard 802.11g, which any modern wireless device can use to an equal degree, and only swap it for a more expensive alternative if necessary.