If you need help with mixing orchestral midi mockops and willing to learn, start with Beat Kaufmann. He might even/probably can do your songs for a fee but I can't even begin to tell you what it would cost so you would need to contact him. He is an amazingly nice person and extremely good at it. He can also provide great starting templates for you to re-use in the future and tweak yourself. Using Vienna Suite and VE PRO, or with Cubase templates if you have Cubase. I suggest you give his templates a try at any rate because they are cheap, good and offer education within themselves if you are willing to just read a little and study what he has done for you.
http://www.beat-kaufmann.com/
The other person who immediately comes to mind is our very own VSL genius DIETZ. He also is very friendly and in fact this is his actual primary education and expertise.
The difference is that he isn't going to provide you an one all template solution and be done. Templates are a great starting place but as I have learned over the years each piece needs some of it's own personality.
If you were interested in learning how to mix yourself with minimal effort, I would highly suggest you get MIR PRO and work with DIETZ for a while. After doing a bunch of songs with him you would have some world class music changing templates to work with. It takes quite a bit of time to get a strong and beautiful balaned sounding template (some of us still tweak them every few months because your ears/taste seem to change) but with assistance of a professional like Dietz this will minimize your impact and push your personal education forward.
If you can swing it, get MIR PRO/VE PRO 5 and Vienna Suite then you can work with both of these amazing people and I am sure get some great results.
P.S. I do not work for, or make 1 cent for advertising or helping you decide. These are my personal opinions and guidance.
Maestro2be