First of all let us know if your piano is accoustical or digital. Both may require quite different systems depending on the recording device.
Secondly, it seems that you intend to record through an audio equipment. Have you considered recording to a PC?
For an excellent thread about how to record an accoustical piano with a PC, look here:
Piano Recording (Recipe and "How-To").
About the suitable mics, there is a lot of information about recording pianos in the mics factories's websites (Shure, Crown, etc). I entered "recording pianos" in a searching site and it worked very well.
I hope it helps.