AWWWWWWW! Poor little bitty baby!!!!!!

You definately need to give her something to make her poop...pumpkin is good. But the thing is, if her poop is too soft, it won't express her anal glands. I would start off with some pumpkin and just get her to poop...any poop at all. Once she gets the hang of pooping, start giving her food that will make her poop hard, like kibbles.
You DO NOT want to get in the habit of having to express her anal glands manually. Hopefully once she gets used to her new home she will start pooping and everything will be fine. My friend has to have her dog's anal glands manually expressed once a month. It is quite obvious that the dog has problems with its rear end...everytime it poops its little hole is so red and swollen. I feel so sorry for it.