I'm sorry to hear your hamster is diabetic, have you consulted with the vet about her? A vet may be needed to prescribe medication in the worse cases (and vets are really handy for confirming the diagnosis too - lots of things have similar symptoms sometimes, although glucose in the urine does definetly strongly suggest diabetes)
This page was the one I found most useful when we had a diabetic hamster -
Diabetes in Hamsters - Vectis Hamstery and Exotics
We mixed his food from scratch and with lots of help, good care and a ton of luck he did quite well despite the diabetes
The website I linked covers it all - A quick summary would be test the urine, consult the vet, then you want higher protein and fibre, lower carbohydrates and fat. You may also need medication depending on the hamsters condition. I personally would never use insulin for a hamster - there are other medications that I feel are far safer and more easily administered (with less stress to the hamster).
Please do not try and treat at home with medications without seeing the vet - its very easy to cause serious harm or even kill your pet if you get it wrong.