I'm not familiar with the field of finance, but from what I have heard, a PhD in finance is well-sought by the industry. And the industry pays well too - especially if you are from a top school.
1. You will never get into a top program if your objective is to work in the industry.
See MIT's FAQ (which is a good represention for the rest of the top schools)
Q: Should I plan to do a doctorate if I want to work in industry when I graduate?
A: Our program prepares people for careers in research and teaching.
2. Taking a 4 to 5 years phd program has high opportunity costs if your intention is to go into the industry. I think there should be good Master programs to help you achieve your career goal. You might find more help at http://www.gmatclub.com/phpbb/viewforum.php?f=86