You said you're in Brazil. I've never been, but if it's warm and humid like a lot of places I've lived in Latin America, you likely can't get rid of the cockroaches entirely. When I lived in my wife's country south of the border, I made it a goal to get to where I'd only see a roach maybe two or three times a week. They if you see even one daily you've got a full blown infestation, so I figured if I didn't see one every day I was going pretty well.
Keeping your place as clean as possible is one obvious thing. Another is to keep it as dry as possible. Cockroaches need moisture, so you want to wipe up any water on your counters, floor, shower, sink, or wherever as fast as possible. Supposedly they hate vinegar, so I'd keep some in a spray bottle and spray some in the cabinets under my sink and other places in the house I thought they might hide. A little around the bottom of doors leading outside too. Just a little, not so much that there would be an overwhelming scent of vinegar in the house.
One of the most important things in keeping the roaches under control was proper use of boric acid. I had to get it shipped from the US, which surprised me, so hopefully you can find it in Brazil. It's a powder that you put down in areas where the bugs are likely to walk. It sticks to their bodies and they ingest it while grooming themselves, which basically melts them from the inside, which is a nice thought became I despise the disgusting creatures too. They can't build up an immunity to it like they can to pesticides. This link seems to explain it pretty well:
I'm back in the US now, in a cold, dry part of the country where we don't have the flying cockroaches, giant centipedes, bot flies, kissing bugs (look it up if you don't know what it is, stuff of nightmares), and hordes of ants I had to deal with in Latin America. I don't miss them at all!
