I have type 2 diabetes that was kind of kept under control by medication, but since August I have been doing quite regular exercise. I noticed literally within days an improvement on my blood glucose levels, and a month ago I was taken off one type of medication, and another one had its dosage greatly reduced. I regularly test my blood glucose levels and find that I only ever need to take medication on days that I dont do any exercise. Therefore, in my case, exercise has rendered my diabetes almost non-existent (although the predisposotion will always exist). Even 2 hours after my main meals, my glucose levels are within the normal range. Both my doctor and diabetes nurse havesaid that this was the way to go if I can manage it.
However, diabetes is such a complex disease that my history and response to treatment/exercise may not be the same for you. Just exercise regularly and see what effects it has on your glucose levels.
If you have a good response, and your glucose levels begin to show an improvement, there may come a point when your medication is too strong and you'll start to hypo - which happened to me, hense the reduction in medication. Hypos are not nice at all, and to have one while running/exercising can be very worrying. If you've never had a hypo before, learn about how to recognise them because you may not be aware that they are happening, and always carry some dextrose or glucose gel incase it happens.
But, this is only advice based on my own personal experience. Talking it over with a diabetes specialist is the best thing to do.