Please do not apologize for your English; I speak no Austrian at all.
I have not been on Volendam but I have been on Veendam which is very similar and just slightly smaller. It was one of my best cruise experiences ever. Everything was first class: food, service, entertainment; and not all the hoopla and razzle-dazzle of the giant ships. (I'm not quite sure how "hoopla" and "razzle-dazzle" translate in Austrian, but you get the idea)
You are allowed to bring a bottle of wine or champagne per person; but they were very lax about that. Many people brought several bottles. Just don't overdo it and there will be no problem. Cocktails and wine by the glass started in the $7.00 (U.S.) range and went higher for premium spirits. Wine by the bottle in the dining room starts at about $25.00 and goes as high as you are willing to spend. If you enjoy wine with your meals, there are wine packages you can purchase that will provide you with a nice variety and save you some money.
Sydney to Vancouver sounds like a wonderful itinerary. We hope you will come back and tell us all about your cruise.