Alternator upgrade

Hello, could anyone help me or provide some information on options for increasing the amperage output of alternators to suit the hj 75 series troopy.
These have the vacuum pump on the back of them and as such i cannot find any units ready made or options bigger than what is made by ingram - being 60amp.
During the day time normal running this is more than sufficient. But when travelling at night time with everything running, stereo, lights, fridge heater etc it isnt big enought to keep up. Also when doing any winch work, they pull around 450 amps under load and with the two batteries hooked together i have to run the car for a full day or put the batteries on the charger in order to get them fully charged again.

Could anyone provide suggestions.

P.S. If anyone is looking for a round oz tourer this is one vehicle you could look at. HJ75 turbo diesel, 35 muddies, twin diff locks, lifted, bullbar winch, snorkel, fully decked out in the back with fold down bed, storage area, fridge, tv and video etc. Has done trip once and would readily go again. I live in Adelaide now and dont have the use for it as much as i did but cant bare the thought of somone else buying it and not using it to its potential.

anyways if someone has suggestions please reply to this post.. i would appreciate it