Help For A Newbie!, Classical musician out of his comfort zone! Options

[jupiterstation]

Hi everyone.

I'm new to the site, so I apologise if I've gone about this posting business incorrectly. I have searched for topics relating to what I'm asking, but can't find the answers I need. I have some very simple inquiries really.

I am a classically trained musician and composer who has been working with Sibelius and other score production software for years. Recently, I have been taking up various commissions for pieces which are either electronic 'pop' pieces or ones for which the client wants a recording without the trouble of paying musicians to perform. I am currently composing a piece for a dance company, for which I need realistic sounding orchestral instruments (as well as some electronic sounds, and various electronic effects)

I have been using Logic Express 8 now for some months, and I'm becoming quite proficient with it; I have produced several tracks for friends (singers, bands) etc, and have got a good grasp of how to use effects etc. However, at present I do not have any hardware - the absence of a MIDI keyboard is the most glaring omission. My query is simple really... What do I need to purchase in order to be able to make near realistic sounding orchestral pieces? I realise I'll need a MIDI keyboard, but I've heard the term 'audio processor' mentioned as well as other things like mixing decks. OUT OF MY DEPTH!

I realise I'm quite young (23) to be asking these questions, but I've spent my life with traditional music theory and composition, and this is a whole new ball game for me! If someone could please provide me with a concise list of what exactly I need, and what I *can* accomplish, I would greatly appreciate it.

SJ

PS. Also, I need this to be on a reasonable budget. Asking for the moon?!