Since it is using a 2S setup, you are in luck.

Get this driver:

http://kaidomain.com/p/S026504.H2-C-22mm-1_5A-1-or-2-cell-5-Mode-Boost-Driver-Circuit-Board-for-Cree-XHP35-XHP50-12V

Get this LED if it uses a 16mm MCPCB:
http://kaidomain.com/p/S026111.Cree-XHP35-HI-Neutral-White-4000K-LED-Emitter-with-KDLIGHT-XP-16-16mm-x-1_5mm-DTP-Copper-MCPCB

If it uses a 20mm MCPCB:
http://kaidomain.com/p/S026110.Cree-XHP35-HI-Neutral-White-4000K-LED-Emitter-with-KDLIGHT-3535-20-20mm-x-1_5mm-DTP-Copper-MCPCB

Good luck!