well horrible and better are all subjective what type of sound are u going for? there's several types of pianos and keyboards with Reason but if the low notes aren't doing it for u on any of those... u could try some EQ anywhere from 300Hz down to get rid of muddiness and not make it clash with your track... if the sound you're getting from the individual notes is not quite as full or detailed as you'd like try layering it and then try some serious cuts on the EQ to take out any parts you don't need and keep what u do
u could also try layering these notes with ones an octave or two higher
if you're looking for a more realistic sound u could try adding a bit of reverb
I'm not sure if you intend to use the sound on it's own or in the mix, but keep in mind if that it's in a mix with a few different instruments it may not matter much after it's all added together you may find the discrepencies in the sound are masked by the overall track
well I hope something in there helps next time try and make your question a little more specific and clear thx!