The same circuit I already drew-up for you works on both ends. Your RF receiver data output pin would connect to the base of the PNP transistor labeled USART, and the PIC USART RX input pin would connect to the PNP collector/resistor node labeled RF TX.

The logic on the PIC USART RX input pin should idle high. With the RF receiver output idling LOW, that's exactly what you'll have on the PIC USART RX input with this same PNP inverter circuit.

It's just basic electronics...