There's a great book called the diabetes code by Jason Fung which I'd recommend you read or listen to on audio book. It will explain why carbs are often a problem for T2 diabetics.
In terms of how many carbs you can eat, that will depend on how you ready reacts. I can't eat lentils without my blood sugar spiking, but a small amount of porridge is fine. I haven't eaten pasta, potatoes or rice in over 2 years! I keep below 50g & that keeps me out of trouble on my HBA1C tests. You probably won't be given a blood glucose monitor but you can buy one & test yourself. You'll very quickly find what spikes you and what doesn't.
Unfortunately, alcohol is also a bit problematic. Beer & Cider are quite carby, but wine & spirits are not. It has some weird affect on your liver so you do need to be careful about how much you drink.
One other thing to note is that exercise does seem to increase insulin sensitivity (which is good even though it sounds like its not). So adding some exercise in to your routine might help as well if you aren't doing anything at the moment.
I went in remission following a low carb diet & have stayed there (just) despite a big wobble late last year which involved far too many bottles of wine, not enough exercise and some cake. It does seem to work as an approach even if very few doctors advocate it currently.