First-- the carolina hikers have a group on yahoo. Check us out at http://groups.yahoo.com/group/carolinas_hikers/ It's kind of an informal group, but folks will take off for the woods occasionally and invite others along.
I suggest a good "practice" before buying lots of stuff you'll likely regret buying and driving many hours to SNP or GSMNP.
The REI in Cary, NC rents gear. It's not expensive if you're a member, and membership is free. A good place to start might be to rent a sleeping pad, bag, and tent and take the pack you have already.
Then, go for a weekender to Uwharrie National Forest near Asheboro, NC. The Uwharrie Mountains are some of the oldest in the US and are under 1000 feet, the forest is gorgeous, plenty of water, and w/in 1 1/2 hr of Raleigh. The Dutchman's Creek/Uwharrie Trail is a figure 8: one loop is around 9 miles, the other is around 12 miles.
You will also have cell phone service.
This way, you can try stuff out, then evaluate what you like, don't like, and you can THEN spend your hard-earned cash on buying stuff and considering what your "hiking-style" is. Don't let all this overwhelm you
ALSO, just a thought question here--As a fellow runner, I wonder if you are more of a "social bug" or a "lone wolf" type. I'm a runner as well, but my psyche tends STRONGLY toward solitude and solo hiking, not group hiking. You may be happier trying it alone, and learing on your own, on a few short overnights/weekends. Just a thought.