Normally I will use the first two usages to express, but still unclear which one is correct, recently I read some German books and find that German can also be used like the third sentence. Which one is right or all three are acceptable?
Correct would be:
First off, all your sentence had the same minor error of putting jetzt at the wrong position. As shown in the answer of Ingmar, you can easily fix sentence one and two.
I'd like to elaborate a bit on the third sentence, which your main concern seems to be. Besides the position of jetzt, there's a second error.
The relative clause (die jetzt an der Uni studiert) can be used as an adjectival phrase, if slightly modified. You already correctly figured out where to put the adjectival phrase:
Ich habe deine [adjectival phrase] schöne Tochter gesehen.
All you need to do (and this is the second error) is using the present participle (Partizip I) of studieren. And, of course, inflect it.
Ich habe deine [jetzt an der Uni studierende] schöne Tochter gesehen.
