You can try a couple things. 1st, visit a couple of the brokerages in your area and talk to the manager about who might be a good fit for your price range. Then you can interview the top recommended agent from a few of those brokerages. 2nd, you can visit open houses in your area and interview those agents and see who might be a good fit for you. 3rd, ask a few neighbors or friends who they used as their realtor. The paper & Trulia can also be an option to meet agents.
There really isn't a good resource for people to look up who has sold what and for how much.
I don't know of a way - I really doubt there is a way of finding that.
Is that what you really want?
Just because someone has the most sales, doesn't mean that person gives the best service - or that they will get you the best price. It's the same as any profession. I'll give you an example of an attorney (not to name names) who was probably the best in town. He put commercials on local TV stations, and next thing you know he has a ton of clients! The problem is he was too busy to be the best anymore..
Rather than focusing on such information, why not consider interviewing a few local agents, or as many as needed, from different realty companies, then choose the one you like best and who has the most to offer...keep in mind that in today's market, pricing and marketing that maximizes your exposure are paramount.