Getting the best piano sound (for your tastes) takes patience; time.
Be creative... move your mics around, try different locations around and in the piano. Heck, even mic'ing the bottom of the soundboard may get you desired results.
The key is experimentation. In the end, your mics just may be the weak point. Go and rent a nice pair or mics and pre-amps, if you possibly can. The expense may be well worth it.