Holden HQ Wagon power steering

Hi lads,I have just got a '73 holden hq wagon,it's a beauty,but I have a power steering problem.......
what is the correct fluid to use in the reservoir?
The fella that had it before me said he uses dot3 for the brakes,AND the power steering..........is that ok?
I always thought that the viscosity in the two might be different.........remembering that I'm not a mechanic,I'm a bloody guitarist...............lol...
anyway,I want to use the correct fluid,anyone got the good oil(lol) on that one?
Thanx in advance,Jonny:)