The amount of gold the party has can be accessed with $game_party.gold
As for time, it is calculated with a bit of mathematics. The way VX does it might be a little confusing, but Yanfly had this code to work it out:
def game_time
@gametime = Graphics.frame_count / Graphics.frame_rate
hours = @gametime / 3600
minutes = @gametime / 60 % 60
seconds = @gametime % 60
result = sprintf("%d:%02d:%02d", hours, minutes, seconds)
return result
end
Which should work to get the game time, you'll then need to add some code to draw the result.
I'm not sure what difference is needed for RMXP if you're using that. I only work with VX.
If indeed that was the info you wanted.