Hi...
I`m Peter an experienced audio-freelancer with many similar completed works...
If you want to get it done professionally - I can offer you me, and my profi designed tools for such edits (from izotope, audition, Sonar++)
..but 1st - I need to get from you your AUDIO /the best in wav format, (or any uncompressed) to not loose quality of source/ - then we can talk about it all, and clear details based on received source...
I do what I can, but I am NOT in might of GOD to do miracles.. I `ll do what is possible..
rgds
Peter