It's not just about the time or money. If rolfy asked for someone to do a voice for his game and offered to put that persons name in the credits, we would be tripping over each other to do it.
Why?
1. Because he has shown that his work is worthy of our time and consideration.
2. Because he has given MUCH to the community.
3. Because we have seen his work and have no doubt that he would complete the game.
Sorry, but we don't know you, and you haven't paid your dues. That and your request kind of sounds like a demand.
But like I said, you should get further along with the game and show us your work. Work with the community, contribute what you can and get to know the members.
Right now advise is free, but remember what you get for nothing isn't always good. The rest takes time.
Best.
I'm sorry, my answers are limited. You must ask the right question.