I like the HOTmilk sets. You can get them on
Amazon
or figleaves. I know there are some other US retailers. Then, you can use them after the baby is born, too. I'm planning on getting at least one pretty set for myself in a couple of weeks.

Also--depending on how you gain, you should be fine in regular lingerie. Most of it is empire waist anyway. Especially if you were busty before being pregnant-there is enough give in the waist. I can still wear most of my pre-pregnancy lingerie. Or hit up a clearance rack at the mall and grab something a couple of sizes larger than you normally wear. Have fun!!