gestational diabetes/diet?

I'm 36 weeks along, and my doctor called and said I have gestational diabetes (it a long story, mostly my fault, as to why it took so long to be diagnosed). Anyway, she said to cut down sugars and carbs, and to try to follow a diet plan for gestational diabetes (I don't need insulin injections)…. it's too far along in my pregnancy to get me to a dietician (takes about a month to get in to see one here), so if anyone has gestational diabetes, could you let me know what kind of things are okay to eat, and how to tell the difference between good carbs and bad?