Ask HN: How to get important people to talk to me?

I've been working for a small company developing a Web app for the past 6 months or so, and before they hired me, I was working on it by myself. They've lost interest in funding it, partially due to financial reasons, but I'm still really excited about the product which is very close to being functionally complete.

Now that I've lost my job with this company, I plan to keep working on this product until it's done, but I feel that a major part of ensuring its success is to speak to business decision makers in my metro area (Atlanta) to get as much feedback as possible. I'd like to know if they'd buy it, and if not, their reasons. I'm willing to make whatever changes will make it more appealing to my potential customers, which are online advertising firms.

I guess my question is, how should I go about getting these people to agree to meet with me? Should I join local organizations of which they are likely to be a part? Should I just call their companies directly and come right out and ask for a meeting? Maybe it's as simple as that, but I suspect it might not be.