My take mate is that you also need to concentrate on your carb intake. You need to be strict till you get your levels down to below 7 at least.
Anything above about 7.5 is possibly (probably) causing you damage!
You'll be amazed at where you can get your levels down to, then you can start seeing what different foods do to your levels. You may think you are being good cutting out the refined carbs, but at this stage you really need to be strict and that includes no rice or starches. And since you are in indonesia you need to watch out for the yummy fruit - it's sugar bliss and deadly. There's lots of threads on lchf diet on this site and elsewhere. basically meat, eggs, cheese, and leafy vegetables. Try it for a few days- see what it does.
I too am not a doctor, but what have you got to lose over a few days of being strict?
The metformin will stop your liver dumping as much glucose (created from the body's stores). As said the glic encourages your pancreas to produce more insulin. But your problem is possibly that your body is resistant to the insulin and so not able to transport your blood sugar into the cells. You need to help your pancreas recover from overwork and also give your cells chance to recover. Too much insulin in the blood/body is also pretty bad for your overall metabolism (leptin resistance). So get the blood glucose level down and that means no carbohydrates - simples.
Set yourself a target level. I personally aim for the 4/5 level, don't often get there and occasionally go into the 8 for a very short time, but by testing I know what to do - and I have find discovered that a short burst of high intensity exercise (5 min) on a bike can work wonders in getting the bg down, better than a tab of glic. I have also tried a fast one mile walk which has worked - there is another thread about getting your hbac1 level down that has some good ideas
All the best and let us know how you are getting on.