Theres no easy way to do what you want without having some kind of small micro on the 2nd board.
An ATtiny would be all thats needed, and a 433 Mhz transceiver.
How often does the sensor send data ?
I was planning on having an MCU on each board. And a transceiver on both. We were figuring it'd be cheaper to design the PCBs normally from scratch, and then just put ports on both to connect each to a 433MHz transceiver board you find on eBay or something.
The sensor is an NTC thermistor. You put 12V in and the resistance increases or decreases with temp, and then the ADC on the MCU reads the voltage on the other side (through a voltage divider clamped at 5V with a zener). To answer your question, it can read anywhere from continuously to probably about 10 samples every three seconds. I'd prefer it to be more like once per second, but I'd settle for a few seconds
You could use a SoC transceiver - it is a transceiver+MCU on a single chip.
Atmel have some, so do TI.
I ordered an 8051 chip with 2.4 Ghz on it. I'll play with that a bit when it gets here.