Cockroaches are the official pet of any warm water port. They will come in from the neighbors, through the drain pipes, etc. As someone said, boric powder mixed with something like peanut butter will kill them. If you have it in your local stores, Bengal Roach Spray seems to be the best of the spray insecticiedes.
I loved the roach motels, they checked in, but they didn't check out. So putting something enticing on an upside down piece of duct tape might work too. But duct tape is a bitch to work with sticky side up.
Moving won't be a solution since the egg capsules can be carried to the new place and the neighbors there may already have them.
Best of luck.