Hardwood floors really shouldn't be washed. There's a chance water could seep in and cause the wood to swell.
To care for my hardwood floors (which is what we have on our main floor), I sweep with a dust mop at least once a day to keep dirt from being ground into the floors. I do spot clean with plain water and a sponge/rag if something is spilled on the floor.
As for keeping the floor shiny, I'm not sure what to tell you. We refinished our floors when we moved in 3.5 years ago, and they still look pretty decent. There are a few high traffic areas that look scuffed, but that's just because the finish has worn off. Have you been washing your floor with some sort of cleaner? That could lead to a build-up on the floor, making it look dull.
Although some people wax their wood floors, it's my understanding that you only wax UNfinished wood floors.