Don't forget you'll need  to extend your   RC   too!  (I'd really recommend it)

Itelite  has  a pretty good    'pilot end'    kit  for our   Q's.     It's about  100 bucks for the kit... and  takes  about an hour to   install.     It'll get  pretty close to your  mile for   video,  and   been tested  up to 8100 feet  for  RC. 

Now,  http://horizonfpvantennas.us/product/yuneec-q500-uav-full-kit/     has   something  that has  caught my eye.. with  several of  Yuneec  guys  really    buzzing about.     About  $135

This is  a  system that  jacks up both the receiver,  and  the   bird itself.  (don't  get fooled by the  'full' part,  it only refers  to BOTH  antennas  reqd.   for the  bird.  (rc and  video)    You'll need  this as well:  http://horizonfpvantennas.us/product/yuneec-q500-pilot-end-kit/    this will be an additional   $205.        Figure about  $100  for each  to have  them  install for you.   It's not that  tough  to do it yourself,  they have  a really good  video series  on  the install.

Now,   which one to get???  LOL,  depends on your area!    I can  almost   'get there'   with my stock  set up.   I am  very   'clean' here  with  very little   interference.    I  truly believe  that the Itelite  system  would   punch me out to  at least a mile.  

For  more  crowded  airwaves,  then   the    horizon  system   would be     my next  recommendation.

  Pilot end.

  full kit for the bird.

Both brands   are  directional type antennas.   you'll need to keep the  top end of your  transmitter pointed  at the bird for best results.

Now,  to answer just your original question for just the camera antenna,   

http://horizonfpvantennas.us/product/yuneec-cgo2-camera-kit/  

Our  Cgo2  camera  has  a  little cloverleaf  antenna  in the back of the  camera case.     Depending on  which way the camera is  pointed,  (up or  down)  will really affect   the angle of the  cloverleaf,  and  really  mess with  range.   This kit   eliminates  that tiny  little  thing,  and  puts  a much larger one   outside (under the belly of bird)  and  in correct  position for max range.   About  $66

You  could  start with  this kit,  see how it  works.  then add  the  other kit if needed.  (they got one  just for the rc part too)..   Just pay attention to which   option on the antenna  you get.   RH  and LHCP   is  the direction of  the windings inside  the  antenna.   You can't  mix them up, or it won't work worth a dang.  (it's  explained  pretty well  on the site)   They identify them  by being either  white or black  housing.    :)