So my concern is that since both her parents had kidney issues, and Lacey herself is a geriatric dog, I absolutely have to put kidney problems at the top of my list.
When you combine that vomiting with the increase in drinking, and the possibility of kidney issues creeps even higher on the list.
Of course, that doesn't mean it's absolutely the cause. The symptoms can also point to things like diabetes, or even other metabolic problems, and there's really no way to know for sure what is causing it without being able to see her and do some testing.
If this were me...since she otherwise sounds like she's stable, I'd give your vet a call first thing Monday morning when they open and have them take a peek at her, and run some blood work to check her kidney function. Of course, if she decompensates tonight or tomorrow, then the best idea will be to have her seen by an emergency vet in your area. If you're not sure where one is, you can go to: http://www.vetlocator.com and plug in your zip code. They'll point you in the direction of the one nearest to you.
HOpefully we'll find out that it's nothing serious...but with her family history, you need to have her vet take a peek.