Atlanta
The problem as you describe it could have two different causes. The first possibility is the so-called "Alkali Silica Reaction" where certain reactive aggregates and the cement products combine. The result is expansion at the aggregate surface which "pops-out" the surface in the pattern you describe. A clear telltale sign is the fact that in each hole you can see a stone. This type of reaction is very bad news. It will not stop until all the reactive material is gone - and most likely the concrete as well. The good news is that whoever sold you the concrete is 100% responsible since the codes require that they test the aggregates and prevent this problem. There are standard tests to determine if this is the case and it is done by a Petrographer who uses a microscope to look at samples of concrete. I suggest you contact the supplier and ask them to send someone to look at the concrete. Most likely they are aware of the problem by now. If they deny knowledge or responsibility you may have to hire your own testing laboratory to obtain and test a sample.
The second (and more likely) possibility is "freeze-thaw" damage where water that soak the concrete freeze under the surface. I assume that there was some freezing and thawing in your area by now. It will cause spalling, but you will not have aggregate centered in each spalled area. To prevent such damage, it is common practice in your area to add an "air-entraining" admixture to the concrete. The air bubbles that are dispersed throughout the concrete allow it to absorb the expansion forces without spalling. In this case, again, the responsible party is the supplier who was supposed to add the admixture (if your contractor ordered it). The way to verify that is to take a sample of the concrete to a Petrographer who will look for these air bubbles under his microscope.
I suggest you start by contacting your local Building Department and asking them about the local experience with ASR (Alkali Silica Reaction) and freeze-thaw damage. Then contact the contractor and concrete supplier and ask them to look at the concrete. Be friendly and firm - your best choice is to resolve it peacefully without a big fight and litigation. If that fails you may have to get a lawyer who specializes in "Construction Defect" litigation, perform the tests, and go after them. I don't know what is the warranty in your case but you should act as soon as possible. And keep good records. Take photographs and measure / count the spalls on a weekly or monthly basis to establish progression of damage.
Legally, I believe you can only go after the entity who sold you the house. They are responsible, and they will have to go after the others who may have been involved. You do not have a contract with the supplier or the sub-contractor and they have no direct obligation to you. (But you should consult a lawyer about that...) You should also check with others in your area to see if they have the same problem.
To learn more on the subject go to http://www.worldofconcrete.com/ and search the article database for ASR and for freeze-thaw.
Good luck.