Well done in everything that you have acheived in becoming the 'MASTER' of you diabetic condition.
I'm sorry to say this, but having been diagnosed with diabetes will mean that you will have this condition with you throughout your lifetime though with good control it may lie there ever present hiding in the background.
Pleased don't get depressed over this issue, as getting your weight under control together with a good balanced diet and sencible exercise will go a long way in helping reduce medications and improving your quality of life.
As to what weight you would still need to loose to reach an optium value, will depend on your height and physical lifestyle, and even using the recommended measurments for both BMI and HtWtR should be taken as guidence only, as no two indivuals are identical.
You are certainly doing the right things so far, so well done.