First, don't touch, alter, or other crumple that dress. It's beautiful. If you do, I'll team up with your Gran and hunt you down.
Steampunk is mostly Victorian and Edwardian era, particularly 1880's and 1890's. However, it doesn't have to be. Some good guidelines (and they are only that) are steam and early electric power, devices, mechanism, brass, iron, wood...corset, goggles and gears are just the beginning. Steampunk fashion also seems to have layers. It's roots are from a time when people wore hats, jackets, coats, watches on chains, jewlery, and purses. Things we ignore nowadays. And that's just what's on top. I think because the dress reminds me of an Edwardian young ladies dress (it just need a large white collar), I keep seeing a mechanic doll.
Okay, enough chaotic muttering, look into Steampunk! by Kelly Link and Gavin J. Grant (It has several cross era steampunk stories.), Robot Carnival (anime, again cross eras with strong steampunk feel), and Expiration Date by Tim Powers (It's a 1990's LA where people catch and absorb ghost to gain power. A boy brings all sorts of trouble on himself when he steals the ghost essence of Thomas Edison.) Tim Powers is also one of the first Steampunk writers.
P.s If you go Steampunk with the dress prepare for people to call it DieselPunk.
Women and cats will do as they please. Men and dogs had better get used to it.