the following is supposed to be a translation of an elementary Chinese text:

Lesson Title:

They use to ask " tuvalet nerede ? "

(Kadın)garson: “Orada!“

I think you can also say:

(Kadın)garson: “Bu tarafta, efendim!“  

"This way, Madam/sir"

It is better if you don´t say "müsaade ederseniz bir sual sorayım"

First: you´d better say "bir şey sorabilir miyim" , "sual" is not used any more in very daily conversations, instead "soru" is used, but here the verb "sormak" is enough. "müsaade ederseniz" sounds uselessly polite in this situation.

Second: you´d better not say this at all, afterall you are just asking where the toilets are. It sounds useless.

- Merhaba, tuvalet nerde acaba? (sometimes "lavabo" is used to ask for the toilets in the name of "politeness".) (you say "lütfen" when you request someone to do something)

- Şurada (efendim). (şurada is better than orada when you are pointing something that is not very far away.)

Thank you very much for great help, "tualet" was taken from "Türkçe-rusça ve rusça-türkçe sözlük, T.E.Ribalçenko, Moskova 2001", of course zargan has "tuvalet"