Welcome to the forum and to glider parenthood.
Does she have a fleece pouch to sleep in in her cage? She may just be trying to get out of the light. Her fur seems cracked and does not look like it is in the best condition and her tail appears to be quite thin.
How old is she? Was she previously with other gliders? She may be very stressed if she was separated from her colony and now is alone. Gliders are colony animals and do not thrive when kept alone.
It is always best to take a new glider in your home to a glider experienced vet for a well check up and fecal tests to make sure she is healthy. If you are worried about her, this needs to happen as soon as possible.
What are you feeding her? Gliders do best when fed a well balanced diet consisting of a nectar like staple that provides protein, vitamins and calcium they need daily. The staple is fed with a wide variety of fruits and vegetables each night. Pellets will not keep your glider healthy long term.
Her fur will improve once she is on a well balanced diet.
If you need information on widely used glider staple recipes and feeding plans I have links on my web page to help you locate the information.
http://www.gliderkids-diet.com/Staple-Recipes.html
As for the biting - right now she is very scared. Her entire world has changed and you are not familiar to her. Let her have a few days in the cage to settle in and adjust to all the new sights, sounds and smells around her before you try to handle her. Talk to her when ever you are near the cage to get her used to your voice. Get a few small pieces of fleece and tuck them in your clothing or sleep with them in your pillow case for a night then put them in her sleeping pouch to help her become familiar with your scent. There are more tips on bonding in the gliderpedia (in the forum header).
Please check the spacing of the bars on your cage. It may just be the angle of the picture but they appear to me to be more than 1/2 inch apart. If they are, your glider may be able to easily squeeze through the bars and get out of the cage.