I think this sentence doesn't match the English sentence... the English says "I should be in bed" -> I should have already gone to bed, this one says "I have to go to bed now"... Am I wrong?

Could you explain what parts do not match each other?

I wrote the first sentence (in Spanish), and then it was translated to several other languages. There were several changes in between - I'm not sure whether they were followed in the other sentences.

ok, here's how I see it:

The Spanish sentence says "ya tengo que acostarme", so the context would be that it's 11 pm and that's the bedtime of the person who's talking.

If you say "I should already be in bed" I'd understand that it's 11 pm and the person who's speaking should have gone to bed some time ago, say at 10:30 pm.

The first English version was:
It's too late, I got to go to bed.
CK changed it to: "... so I should already be in bed."

The truth is, I don't see it as you do; when I read "I should already be in bed", I do understand "ya tengo que acostarme". The scenario I have in mind is that the time is past bedtime (say, I usually go to bed around 10:30, and it's already past 11).

"Ya tengo que..." - does it mean: ..."I already have to..."?

I'd say "ya tengo que irme a la cama/acostarme/..." when the time is not past bedtime, but when it IS bedtime, otherwise I'd say "Ya debería haberme ido a la cama/a dormir".

OK, well, my Spanish version was the first of all the sentences in this thread. Do you think the English should be unlinked?

(I'm still not sure I agree with you, it seems that on these bedtime subjects we have some disagreements ;-))

Let me explain: I believe I disagree with you not on how to understand the Spanish, but on the English rendition of my Spanish. I believe it could be translated like that and that the original meaning was still retained.

hmm you forgot to tell me that Marcelo had written the original English sentence :P then I guess I can't complain, maybe in Chile this sentence means that...

Indeed :)

I still wonder if other English sentence still matches