Tennykins, when I had my Glucose Tolerance test it was only my fasting reading that was high (was 6.8 and should have been under 5.5). I now take a shot at night of a long lasting insulin and my morning readings have been perfect ever since (granted it is quite a high dose but if it works....).
Have you tried uping your exercise? I tried it this time and it didn't seem to have much of an impact. It was almost a relief to end up on insulin as my results have been sooo much more under control, even when I do have something bad. If you end up on injections it isn't the end of the world. Whatever it takes to have a healthy baby, right? Like you I was diagnosed with it pretty early in the pregnancy. Do you see an endocronologist or just the diabetes educator?
THey will usually give you a couple of weeks to try and get your levels down, so don't stress too much if you can't do it straight away. Some foods which you don't think will affect you, can sometimes really bump you up, so experiment a bit. I also find portion sizes have a big impact on levels as well. Lots of a low GI food will actually mess with your sugar, while a little doesn't. THis of course leaves you hungry, so I found salads to be a life saver. Also milk with milo was good for a snack.
Any questions please ask. I have been in exactly the same place you are, and the whole thing can be a bit overwhelming.

Caz, Mel is right. THe educator will work with you to work out why the readings are high. Portion sizes, poor food choices, will exercise help? You usually have a couple of weeks to experiment and see how you go with diet, but for some people (like me) diet and exercise doesn't have a huge impact on my levels. Talk to your educator though and find out at what point exactly she will refer you to a specialist. Are you writing everything down to show her? This I find always helps as patterns can be seen much easier.

Good Luck!