At what point might I begin to see improvement?

[na9999]

Hello, last week I woke to my 12 year old terrier on the floor, very limp and tired. I took her to the vet and she was diagnosed with Kidney Disease.  Mon-Fri last week I dropped her at the vet first thing in the morning and picked her up in the evening after spending the day on IV fluids.  She came home Friday evening and I am now giving her subcutaneous fluids. She is taking Phos-Bind and Potassium Suppliment Renal K with food and takes both well.  The vet has suggested I have her eat something enticing, so I'm feeding her boiled chicken breast, which she enjoys. She is eating and drinking well. The vet says that some dogs remain hospitalized for weeks on IV with this condition.  My question is when might she begin showing real improvement?  She is still very lethargic and sleeps about 90% of the time.  I'm happy to continue if she will improve, but don't want to put her through this if the likelyhood of improvement is slim.  I want to make sure I'm doing this for her and not me.  She does not appear to be in any discomfort or pain, but again if this is her future, it's not one that I want for her.  She gets up once or twice a day to go outside to urinate, but other than that she's mainly sleeping.  Any guidance from those who have been down this path?