Right, you need an insecticide containing Permethrin - ant killer seems to do it.
YOu need to find the source of the infestation - an old sofa? Or on old rug? they particularly like fur, feathers and wool.
But you need to OBLITERATE them with the insecticide, then hoover DAILY, everywhere you have ever seen even one, because the larvae (the spiky caterpiller things) move fast, and the beetles can fly I think. They breed fast too.
Look under all your furniture, wash as much fabric in your house as you can (curtains, covers, ALL clothes) and give drawers a good wet clean out.
I feel sorry for you, they are very hard to shift. I had them last year, and had to throw a sofa away (which, having bought it second hand and it being stuffed with feathers, I assume was the original source of infestation)