There are options, but I'd probably just run it right off your battery pack.
I see you have a 6-cell NiMH pack, and the specs say it can operate on 7-cell, so you won't quite see it's full potential. Another option is to get a CC BEC and run both the winch and your steering servo off of it. This option would be best if you were running 2 or 3s Lipo and a high voltage steering servo with the BEC set to 7.4V. Finally, you can get a small 2s Lipo if you'd like to give the winch it's own dedicated power supply. That's probably only a viable option if you already have a Lipo-compatible charger.
What I wouldn't do is run it off of the ESC as to not overload its internal BEC.
Ya I run that 6-cell on those long trail rides. Seems to last forever. I do also run Lipos most of the time and have had a castle bec in my wraith to power the rest of the truck. This is my first time with a winch so did know if it needed that much power.
Thanks for the info