I'm an instructor and I take a classes as a student on a regular basis as well.
Here are some of my recommendations based on your existing shooting background:
NRA - Personal Protection Inside the Home - This is the NRA's "home defense" class. It's more then just shooting and is a good way to get your feet wet in defensive training without having to travel or pay a lot of tuition. It's a one-day or two-day class, mostly classroom, and you should be able to find a class nearby. Total class length is about 8 to 10 hours.
NRA - Personal Protection Outside the Home - This is the NRA's "concealed cary" class. It's also a mix of classroom and range, but more range time then PPITH. Depending on your skill level, and the instructor, you may be able to skip right to this class. (Students are supposed to show skill equal to passing the PPITH class, but my understanding is that technically they don't need to have taken the PPITH first if they show comparable skill). Class length is about 12 hours.
The advantage of these NRA classes is that you should be able to find them locally and the are fairly inexpensive. The disadvantage is that they are pretty basic for defensive shooting classes. That may be what you need, or you may be ready for a more advanced class.
You sound like you'd do fine in Gunsite 250 or the "Level 1 handgun" equivilant at any of the big schools like Thunder Ranch, Shootrite, DTI (John Farnam), Louis Awerback, etc. These classes are going to be much more focused on shooting then the NRA classes and generally be a little more cutting edge in terms of the techniques.
You should also consider Massad Ayoob's LFI 1 class, The Judicious Use of Deadly Force. It's more then just a shooting class: You'll send about 20 hours just learning about the moral, ethical, and legal implications of using deadly force. It's a great class for any concealed carry holder. The class breaks down into about 24 hours classroom and 16 hours on the range.
Don't worry about your skill level. If you are already a shooter, you'll do fine. The instructors are used to having people with a wide range of backgrounds and experience. You'll probably be in the top-half to top-third in terms of firearms experience.
When I took LFI 1 the women on the line next to me actually had to ask how to load her brand new pistol before we shot the first course of fire! She wound up getting a little extra attention from the instructors and did fine. The student on the other side of me was already a NRA instructor and former cop. Appropriately, back then I was about in the middle of those two in terms of my shooting experience and skill.