1. The important questions for the investor are 1. How much do we need to invest ? 2. What will be the return ? 3. What is the risk ? Maybe you should turn your presentation around those 3 questions.

2. Make it shorter. I like the 10/30/rule of Guy Kawasaki (Venture Capitalist): 10 slides, 20 minutes, 30 points font size...

See this video as from 24 minutes... http://video.google.com/videoplay?docid=-3755718939216161559#
Kuy Kawazaki proposes this structure for the 10 slides:

1. Title
2. Problem
3. Solution
4. Business model
5. Underlying magic
6. Marketing and sales
7. Competition
8. Team
9. Projections
10. Status and timeline