One Sutta / Text which covers all of Buddha's Teaching Which is the one Sutta/Text that covers all of Buddha's Teaching? I require only one book which I can carry with me and it should have Buddha's delivery in original language and its translation in English.
You'd be hard pressed to find a single sutta that covers everything.  The suttas really don't work that way.  To compound your difficulty, you'd be even harder pressed to find an English/Pāli version of any text!  If I had to pick one sutta from the original canon, however, I think I'd go with the Sāmaññaphala Sutta.  It does an excellent job of providing a bird's eye view of the gradual training in the least amount of space.  You can find the Pāli version of the text here.  It's in the Tipiṭaka under the Suttapiṭaka, Dīga Nikāya, Sīlakkhandhavaggapāḷi, Sāmaññaphalasuttaṃ.  (I'd appreciate if anyone can link that directly!)  A bound copy is available here - but again, no Pāli.  Bhikkhu Bodhi also did an excellent translation of the sutta and its commentaries.  That's available here.  If you are going to spend the money, go with his version.

There are other single, bound texts that are far more detailed, technical, and honestly, I'd say more helpful.  Key among these is the lengthy Visuddhimagga written by Buddhaghosa.  Seriously, that guy spares no expense on detail.  I swear he thought he was getting paid by the word!  It also meets your requirement in that it is written in the [supposed] language of the Buddha - Pāli.  Mind, it was written several centuries after the Buddha's death.  The original text is also available on tipitaka.org.  It's under Anya, Visuddhimagga.  A bound copy of this book weighs about five pounds.  I'm not kidding.  It's not something you'd want to carry around with you.  A dual language version would be enormous!