Recommendations For Small Hardwood Floor Cleaning Machine?

Can anyone recommend a hardwood floor cleaning machine? I'm looking for a smaller type cleaner as I don't want to lug a heavy machine up and down two flights of steps.

By the way, my floors are oil stained and hard waxed, there is no poly on them.

I know I am not supposed to use water on the floors but I have a dog going through Chemotherapy and she has accidents when I am at work.

Thanks so much!

Jennifer from Northern Virginia