microstrip antenna - power + range

i designed a microstrip patch antenna for 2.4G . now,

1) how do i calculate it's power handling capacity (i know it's like an capacitor with plates of unequal areas)

2) wat would be the range of such an antenna if the same antenna is kept as tx & RX on top of say buildings with LOS data link!
how do i know the range of the link? ( ny practcally used formula for LOS range measurement)