AM transmitter designed for short distance

hi,

i am trying to design am transmitter for short distance to learn basic calculations of transmitter

AM TRANSMITTER

modulations type am modulations
frequency range 1mhz
voltage supply 12v
transmitting distance 80m-100m
audio frequency 20hz-20khz
antenna
low level modulated with linear amplifier

i know i need following circuit to make transmitter
audio amplifier circuit
Oscillator circuit
RF amplifier circuit
microphone

i need circuit that amplify the signal of mics
i know to make amplifier circuit
transistor NPN, PNP transistor
mode ce, cb, ce
class A, B, C amplifier

for design audio amplifier we select following parameters
audio source -microphone
transistor npn transistor
mode common emitter
class class A power amplifier

transistor ratings
collector emitter voltage=30v
collector base voltage=60v
emitter base voltage=5v

collector current=800mA
power=500mW

microphone ratings
frequency response 20khz
impedance 2k ohms

my questions
what is gain of audio amplifier for am transmitter
give idea to know what type of amplification we required
single stage, two stage, three stage .... which stage i used for am transmitter

please explain with mathematical calculations
i don't care bad quality of transmitter


thanks.................