First off: Welcome!
Now to your questions. I have had no experience with the HPW sold by Exotic Nutrition, but have hear that it is good. Still, I would recommend you try to do some more research. In the gliderpedia you can find more about diets:
www.sugarglider.com/gliderpedia/index.asp?Diet
Some of the mainly used ones are BLM and HPW. The BML was created by Bourbon, therefore the Bourbon Leadbeatter Modified . All of the ingredients for this diets can be found in your regular grocery store, BUT it is very strict diet and it requires that you follow it exactly as she wrote it (any modifications will throw off the balance). Then, the HPW I am familiar with was developed by Peggy Breuer, besides the powder you will required either just water, or a combination of eggs, honey, and bee pollen. Her site is below:
www.critterlove.com/food--sides.html
And you can find more information about the different types here:
www.critterlove.com/diet-info.html
Candy is a member here, and she develop her own diet, which you can find here:
www.gliderkids-diet.com/
If you have any questions I am sure she'll be glad to answer them.
Pellets should not be their main diet, but many here feed it as a daytime snack, in case they wake up hungry during the diet; and many agree that it helps keeping their teeth clean, since it simulates biting into bark, which they do in the wild. Though in order to accomplish this, they should not be soaked in juice. You can keep using the pellets from exotic nutrition. What I use is Pet-Pro's pellets which you can find here:
www.pet-pro.com/index.php?main_page=index&cPath=2&zenid=fgj4aacqqdj2epjnondhd09g42
The main thing about diets is that you should keep in mind the recommended ratio of Calcium to Phosphorus, which should be 2:1. It is because of this that my main concern about what you are doing is the sprinkling of the extra vitamins and calcium, since it is impossible to tell how much you are giving her, you could not be providing her with enough Calcium or too much of it; either case will affect her health. So my recommendation would be to stop doing that. Candy have a list of safe fruits and veggies with their Ca:P ratios, you can find it here:
www.gliderkids-diet.com/FruitVegLIST2011.pdf
Though it is hard to keep it exactly at 2:1, providing a wide variety of fruits and veggies should help balancing their diet out.
My other concerns are:
1. Have you taken her to a glider experience vet? This should be done, as with any other pet, so she can get an initial wellness check and fecal test, to look for parasites, since the people you got her from don't sound to have been taking good care of her.
2. Are you planning to get her a cage mate? Gliders are colonial animals and do better, physically and mentally, if they have a glider friend.
3. Does she have a wheel in her cage? If she does, is it glider safe? If you are not sure, please take the time to look at these wheels listed here:
www.sugarglider.com/gliderpedia/index.asp?ExerciseWheels
I know at first it can be hard to care for these little critter, but with time you get use to the routine, and find out is really does not such a difficult task.
I am sorry to hear about your cancer, and hope you get better, and that with this new companion you feel better.