Ticks on dogs? They won't go away?

3 months ago or so, my dad put new mulch in our backyard. Since then, we've been noticing ticks on our two dogs. We've been putting Frontline Plus on them (once a month), had our backyard bug sprayed, and the dogs have flea/tick dipped, but we're still finding a bunch of ticks on them. Now, we're starting to find them in our kitchen (where the dogs stay). My mom just found one on the floor crawling around. How can we get rid of them completely?