Diabetic dilemmas. 47 lbs lost, 20 to go!

Yourself
Hi! I'm Crystal.... I've lost quite a bit since starting MFP in 2011. Most of it happened early 2014 after I quit alcohol and started the Byetta injections. I lowered my A1C from 11 to 7.4. Problem is, I've been at a plateau since then and nothing I do seems to help me with this last 15-20 lbs. The whole theory of "just take in less calories than you burn", does NOT work with me. My body got messed up from radiation treatment 20 years ago and lost the ability to process sugars.. now I'm diabetic. Has anyone out there with diabetes figured out how to break a plateau?? I'm gearing up to get rigid with carb counting and aiming for 20-50 grams a day in hopes that will work. ...what's your experience?