ID-12 wireless

So I've connected up my ID-12 RFID reader module (a la HC Gilje) and its all working great, I can see the tag ID's coming up in the serial monitor.

I now want to transmit this wirelessly and I am looking at using a RF transmitter and receiver. I was having problems, so in order to test things, I powered my reader from a second Arduino and put the serial out straight into the RX of the first Arduino. It is still scanning according to the LED, but I am not seeing anything in the serial monitor. I feel as though I am missing something fundamental here. Any clues? I tried another power supply, but it seems if I don't power the reader from the first Arduino, I can't read the serial output.

(By the way if you've got a better way to transmit this wirelessly, preferably not involving two Arduino's and NOT bluetooth, then I'd love to hear about it! Would WIFI be a better option?)

I don't think I'm understanding exactly what you're doing with the two Arduinos, but I'm guessing you've joined the grounds of the two devices...?

I would recommend the Xbee for your wireless question. They're very flexible, fast and just generally cool devices.