I think the idea you had about the bathroom during the day while you are gone is a good idea and at night you could crate her in your room. One of my yorkies very small and she is full grown, so she still can't hold it through the night, so I have a wire crate ( I think it is medium size) and in the back I have a rubbermade storage container big enough for her to sleep in and I have blankets in there, then in the front of the crate I cut a puppy pad in half and place it there for her to use at night. The storage container keeps her bed off the puppy pad. She just jumps out of her bed and potties and then gets back in the bed.
Like some of the others said before, 7 weeks old is really young for a yorkie to be away from their momma, but I think she will be fine as long as you give her lots of one-on-one attentions when you get home. She will need lots of walks and play time after being alone for so long while you are at work.....good luck...
