A good shoe store will actually be able to help you a great deal. By "good", I mean that their service people can identify whether you pronate or supinate, know which brands' shoes are wider, narrower, etc.
A lot of people buy running shoes down at the mall, and are sold the latest flashy shoe from Nike or some other big name, with little to no understanding of shoe fit.
Talking to an local pedorithist, running group/coach, or trial and error should help you find a shoe store with the right sort of service people.
Good luck!