Hi.
The best thing to do now is to get that DNA test as long as they're paying for it. If they don't wanna pay for it, then they should at least meet you halfway and pay for half. I know you feel insulted but let it be for now. Get the test because that actually gives you some legal leverage. If the baby is proven to be his, and you it is, the mother has no choice but to shut up. He, on the other hand, will be put on the spot to be more responsible.
I'm really sorry but this, and other things like these are just what goes with early pregnancy especially that which happens out of marriage. Since you said you wanted to have the baby, start fighting for your child. Right now, you already have to be strong enough.
Be strong and pray a lot.
Erick