I need advice! Looking to buy a new, lightweight bike......Any recommendations?

I have to carry my bike up a steep flight of stairs and into my apartment so I need a very lightweight bike. I need a bike for short distances, i.e. under 10 miles per day. I am 5 ft 2 in. and weigh 130 lbs. I am looking for an every-day bike that weighs around 25 lbs or so max. I am wimpy. Not only am I wimpy, i am broke and need the bike to be under $175.

PS I don't like flat bar rides and prefer a step in bike, 26 inches but I may fit in 24 inch bikes ok.....