You could refer to it once or twice or integrate the quote into whatever you are saying like, for example (making this up) "The island on the Tempest combines several features that resonate strongly with the imagination of the audience. There is the shipwreck, storms and the magical inhabitants of the island. This is seen when Prospero, blah blah 'insert quote"(Act1, Scene2)". You can like, just reference your quote in brackets to suggest to the marker that you indeed know what you are talking about and where it is.
But by all means, of course you can reference by saying "this is seen in Act1, Scene 2, but i wouldnt worry too much about it refercing at all though. I think the relevance and mention of the quote will be fine. For my generic essay, i didnt write what scene, i just said Act. OR you can call the HSC help line...opens in 15mins. 131112. English teachers ive spoken to are awesome.
Im sorry if i confused you or something, cos i dnt even know what im talking about right now.