The amplifier with filter from rtl-sdr is highly praised.
You’ll need an rtl-sdr dongle as well to supply voltag the amplifier/filter combination.
https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
Or with you current setup you can try one of the SAW filters that are available, the flightaware filter is nice but SAW filters can depending on the noise level in your location improve reception quite a bit.
Or you could try the blue flightaware stick which is not too expensive i believe it has a SAW filter built in.
All that stuff also depends alot how limited by your horizon you are. So how high do you have your antenna positioned?
Anyway it always depends on what price range you are talking about, there are pricier upgrade i believe this recent thread discusses the pricier stuff: