There is a good chance the ammonia is a false reading. I would take a water sample to your LFS
for verification. Ammonia will generally become undetectable after about 2 weeks unless there is a heavy amount of nutrient and less than desirable bacterial surface area's. The nitrite can take as long as 8 weeks but will usually subside in 4-6 weeks again depending on nutrient levels.
Do you have any nitrate readings yet?