Hi soh15,
Like frog girl says, the live plants will help the fish by controlling the ammonia and nitrite, but will still leave enough for the bacteria to grow and finish cycling your tank. The Ammo-lock product will take the ammonia away from your fish, but then I don't know if the ammonia that's absorbed by the Ammo-lock is available to the good bacteria. So, you may be "starving" the bacteria and your cycle will stop or stall. I would just go with the plants you put in there, stay away from this type of ammonia-absorbing chemical, do daily water changes if necessary (I did daily water changes for three solid weeks once so I know how it is) and it wouldn't hurt to feed every other day during this time of high nitrites.
Do you have an ammonia test yet? The fact that the nitrites are high probably means you are done with your ammonia spike, and it will be 0. You should always have an ammonia test kit on hand though, but keep doing your water changes until nitrites are 0 too. Depending on your bio-load, nitrates will be anywhere from 20-40
ppm. Usually, you don't get under 20
ppm nitrates unless you have live plants (which you do) or have a light bio-load. A cycled tank will always register 0 ammonia and nitrites, and the nitrates are lowered each week with the partial water change. If you can, though, get test-tube type kits. I did have a strip kit once, and it always said 20
ppm nitrates, no matter what I tested -- aquarium, tap, or bottled water.