I work in Pest Control. The main treatments we do for roaches includes a few chemicals. You can get them off eBay, depending if it's legal in your state.
Phantom (termiticide) : has a long residual
Gentrol (IGR) : a additive, used as a Growth regulator to a insecticide/termiticide
You would mix a ounce of each to a gallon in a sprayer. Use it to go along the base boards and under the sink. The chemical Phantom, is a passive aggressive termiticide. It acts like cancer to roaches and slowly kills them off