Off the bat I would say to try some easier stuff first.  I would set this as an intermediate-term goal.  Would you be satisfied if you could transcribe this and play it six months or a year from now?

You need to define how complete and accurate you want the music.  I guess you could transcribe the whole orchestral piece into a software file and then you play the violin part.  Do you want to have the violin replace the vocal?  Do you want to end up with a stand-alone solo violin piece you can play?  Do you want the full length, or just to be able to play a few key parts that evoke the feelings of the piece?  I think you have to be inventive and adaptive to do something like this.

You need to say something about whether you can read and whether you have transcribed or adapted anything before.

Maybe twice a week I will hear something I want to learn or remember, so I write the music for it.  I use a program called MuseScore, which is free and works pretty well.  After you write, you can play it back to hear whether it sounds right.  You can score a symphony with dozens of parts with it it you want. Often I don't transcribe the whole piece, but just some key parts.  Maybe I don't intend to develop the piece completely but just write something, planning maybe or maybe not to come back to it.  I've done only a few pieces that have more than one part.

I use a tuner to find the main pitches of the piece, then I fit the rest of the tune to that.  I choose a note that I hear, then I sing that note into the tuner so as to know what note it is.

cdennyb said
You people that are gifted like that never cease to amaze me!

How incredible it is that you can listen to a piece and write the notes that correspond to it... amazing and magic I say...

I hate to break my own mystique, but it is no more magical than being able to listen to English and write down what was said.  The first step in doing that with English is to be able to repeat a word that you heard.

If I were to play a note on my violin and would repeat it every time that you asked, do you think that you could match the pitch by playing a note on your violin?  I mean could you play the same pitch that I played?  And if you could do that, could you "read your fingerboard" to know the letter name of the note we both played?

I guess that musical literacy goes like English literacy.  You improve your reading and writing at the same time.  You could listen and speak and repeat before you could read or write. 

Not that everybody has to be good with sheet music.  I guess none of the Beatles could read or write.  Of course they didn't need to, since they were leading the way.  But I feel that not reading is an unnecessary limitation.  A lot of people get scared that it is too hard, when really it is not all that hard to learn the basics.  It is a kind of fairly simple code in the way that the alphabet is a code to the sounds we make when speaking.  In the same way, some people never learn to read English, whereas if somebody just explained phonetics to them, they would basically be able to read after ten or twenty hours of study.  I would say with both English and music, writing correctly is harder than reading correctly.