A few problems right off:
(1) You need a lot more rock - rule of thumb is 1-2lbs per gallon - so you need at least 30lbs of rock. You can buy dry rock, which will turn live over time. Rock provides surface area for nitrifying bacteria to grow on, and without enough rock you won't have enough bacteria to process the ammonia and nitrite in your tank.
(2) Flake food can lead to all sorts of problems with your water parameters (though more nitrate and phosphate problems). I'd switch to frozen cubes instead - marine cuisine, frozen mysis, emerald entree, etc. And I'd only feed about 1/4 to 1/3 of a cube every other day. You're fish will do just fine on that amount. With frozen food, just cut off the amount you are going to use, put it in a little container with tank water, swish it around to thaw it, and then use a turkey baster to squirt the food in the tank. Not only will it help with water quality, but also nutrition.
Your test kit should be okay, but if you don't see any movement in the numbers after adding more rock and changing food then you might want to have your LFS double check the numbers for you.
Also, how did you cycle your tank before adding fish?