I currently have a pagerank 5, im predicted to jump to a six, I really want to shoot for a seven, How many links will I need to exchange / purchase to meet this goal. And does it really matter if it is the same niche?
The number of link exchanges you get is not important. The quality of the links are. To get to a PR 7 you would need to get your link on PR 7 pages. That isn't exactly easy to do, though I'm sure there are some people here with PR 7 sites that would be willing to give you a link for a monthly payment.