Is she pregnant or with baby in pouch? If she has a baby in pouch then he pouch will get poofy looking over time. She will have one lump if she's having one Joey and two if she's having twins. Twins are harder to tell because she'll be symmetrical which can be mistaken for being fat. Or at least I mistake it for fat XD
You would keep her by herself until you are positive she's not expecting or until she has the Joeys and they are old enough to live on their own.
Usually sugar gliders that are bonded to each other will help raise the babies ( at least that was the case with me). Sugar gliders that aren't bonded and come from a different pod can kill the babies.
Expecting gliders need more nutrients than the average glider. Especially protein. You'll probably have to give her extra of her staple. Some times the diet might have special instructions for expecting gliders. So yeah look into that.
www.sugarglider.com/glidergossip/topic.asp?TOPIC_ID=54797
I found this thread to help me when I had an expecting mother living with a male that wasn't the father.