How can I get a brick out of my drain pipe?
First, do not attempt to break the brick into any more pieces, should you succeed these pieces may get lodged further down the pipe making it that much more complicated (and expensive) to resolve.

Unfortunately the only solution will be to cut the section of pipe that the brick is stuck in and remove it.

Call a plumber: it already sounds like you are in over your head; a qualified professional will be able to resolve the situation for you without further compromising the drainage system.