Video stream over RF
You state frame size and resolution per pixel but no refresh rate. Assuming one frame per second, the data rate is: -

640 x 480 x 8 bits per second = 2.4576Mbps.

There are no cheap off-the-shelf solutions for this (even at one frame per second). For instance Zigbee will work up to 250kbps. Nordic NRF24L01G is good for 2Mbps and you might get 20 metres at this bandwidth and operating frequency but remember it only produces an output power of 1mW.

The best option you have is to compress the data using something like MPEG methods - this could reduce your streaming data rate by a factor of ten and then you have a chance of getting something off the shelf.