Yes and Yes.
If you're looking to start a colony, you'll most likely want quite a few more.
Either adults (for faster starting) or a bunch of mixed nymphs (for less cost).
There's lots and lots of threads around on Dubia's, I'd try to go read a lot of them,
and go through several "caresheets" too.
I started my colony with 50 Adult Females, 10 Adult Males, and 250 large Nymphs.
(at this size, it should take me about 2-3 months before I can start feeding from it at all,
and probably 4-5 months to be completely sufficient for a young dragon)
You definately need an extra heat source. Dubia's need it to be 85-95 F to breed.