Hello and Welcome to YT!
I would be very careful of using multiple products on my Yorkie. They can be very toxic alone and deadly used in combination. Some Yorkies can have an allergic reaction to flea and tick products.
I would consult my vet about my dog, and then consult a local pest control company about treating my home. Be sure to tell them to use a pet safe product. I can't recommend anything else as I am unfamiliar with the type of ticks and the environment you are in.
In general, ticks will attach to an animal or person to feed. Once they are full, they drop off and live anywhere until it's feed time again. Vacuumimg frequently may help. Diatomatious(sp) earth for corners and the yard... look into Boric acid (non toxic)
Article I found:
thebahamasweekly.com Tick Borne Diseases
The author gives her email address at the end, maybe ask her if she has found any good solutions for treating the yard. So far, I've read to keep the grass short, eliminate woodpiles, and ticks are fond of trees. If preparing your yard is too much, consider preparing an area specifically for your dog...