It seems very flawed to only create and develop design for the clients you already have. If you only take into account your current client base, how can you ever plan on growing your business even further? Yes it is possible to grow steadily with your current clients by designing and developing websites for them, but most business owners I know, including the owner of Integraphix, are constantly looking for new outlets for business and networking.
By expanding and growing a business, we assume that a graphic design business owner is looking to gain new clientele that are perhaps different than the clients they already have. They will be fairly similar and should be so you don't have to expand your targeted marketing, but some may be entirely different and this is a good thing!
Look for clients that might be outside of your typical client profile. This allows you to get feedback on your business, design and services and gain valuable insights in order to gain market appeal to a larger group of people. Try it out and see what kind of results you get.