@college123,
It sounds as if she truly did think it was the guy she was dating. I suspect now that the baby is a little older, he has questioned whether he is the Father or not and has etablished that he is not. Hense, her request for your boyfriend to have the DNA test.
For all you know she could be telling the truth. She could purely want her child to know her Father. You say that both of you intend to be in this childs life, good. It's not the child's fault and children should always feel loved and wanted by their parents, regardless of whether they are together or with different partners.
It may very well be later down the track that she asks for assistance, your boyfriend could do the right thing and offer it now, meaning, some clothes and things a baby needs. You could establish that she even says "no thank you".
You can only speculate what her intentions are, but you can give her the benefit of the doubt and allow this little one to just be happy amongst his Mum and amongst his Dad and you.