You have received great advice already concerning the brush. I use a small plastic child's brush. And yes, brush daily. Expecially with long hair. Or keep the hair short.
I know pet owners do it all the time and I don't say this to offend anyone but, do you need to bathe your yorkie every week? They don't really need to be bathed so often unless they are dirty or spend alot of time outside getting dirty. Usually yorkies are inside dogs and live a very pampered lifestyle.

I remember reading (this was a while ago) that yorkies need to be bathed about every 6 months. I bathe or have my baby groomed a little more often because she sleeps with us. But I have never bathed her weekly.