The word ober can still be used, but you usually do so when talking 'about' the ober, not to address them. Same goes for 'serveerster', when talking about a woman. When addressing them, you often replace ober/serveerster simply by meneer/mevrouw or by saying sorry (excuse me).
You can say ober to a waiter, but not serveerster to a serveerster, that's always mevrouw, but as mentioned before, simply saying mevrouw/meneer or sorry… is more common.
Funny indeed that this evolved/is evolving differently from German. BTW in a Dutch snack bar there normally will be no waiters at all, you have to get it from the counter yourself (or out of the wall…) You need to go up one step in luxuriousness to a lunchroom for waiters to appear. :)
The word 'like' as in the sentence above seems to be used as a filler, especially in teenager slang.
As to 'go like', an urban dictionary gives the following definition:
The most common two words used in a sentence by girls from the age of 13 to 18. Can be used up to 5 times in a sentence. 'The girl opposite me was talking to her friend: "Well I was like disgusted with her and I go like "You're a ❤❤❤❤❤", and she goes like,"Well, like tough ❤❤❤❤❤❤❤", and I go like, "you should like be so lucky", and my friend goes like ...' .
Here are two possible situations at table.
(1) At the start of the meal, the host asks, 'What do you want to drink: wine, beer..?' Answer: 'No, I want water, please'.
(2) During the meal, when your glass is empty, you could say to someone who has the water jug: 'Could you give me some water, please?'