It sounds to me like your pup needs to be hospitalized. There is NO way you can give your pup enough water...or pedialyte...or any liquid to prevent/cure dehydration. Subcutaneous fluids can help, but are not always successful.
My suggestion to you is to find a way to do as the vet suggested and leave her there for appropriate treatment! If this is a money issue, perhaps you can apply for
Healthcare Financing Credit Card | CareCredit Having one sick pup is expensive enough...but two? After this, I strongly suggest you look into pet insurance. Yorkies can and do become very ill quickly when having GI issues and can die if not treated promptly and correctly!
Hope things are improving. If not, I would definitely not leave her alone while going to work.