bh1415 amplifier

I have a transmitter based on the BH1415 chip. What would your suggestions be for boosting the small RF output to 100mW output. The device is intended for a large farm in Namibia (2km range), where the main house must communicate with the worker houses - using a regular FM radio.

I am currently thinking of using the MAR-8ASM monolithic amplifier. Is this a good method of amplifying the signal. The output from the MAR-8ASM will be in the order of 10mW, and not the required 100mW.