The vet has a pill that kills them almost instantly (i forget what its called but its like 2-5$ a pill) but you might have to bomb your house. They get into your carpet, couches and everything. I'd continue on the frontline too. A good place to get frontline plus is
http://www.petsuppliesnet.com/list.htm - I've ordered from them a ton of times. It takes a bit since it's coming from Australia but has worked for me.