How well the antenna works depends on which frequencies you are most interested in. The higher the frequency, the worse the indoor antenna is because the walls of your building are reducing most of the signal.
Even if you could get the stock antenna *outside* - even just outside your window, you would see an improvement.
Other than that, you could try a mobile mag mount type scanner antenna that is designed for the frequencies you are most interested in.
Mount the magnet on a cookie sheet and try and get it near the window. Optionally a metal file cabinet, radiator, etc - but go for something flat and solid so the magnet can "couple" the antenna to the "ground plane" of the cookie sheet, etc.
Or mount a discone type antenna in your attic.
With antennas, location is most of the battle. A ****ty antenna at 35' in the clear will run rings around the best antenna that is located inside a house.