Pet rat keeps biting me

Question
2 weeks ago I bought a female rat from a pet shop.I already had one male rat at home who is very sociable and loves to play around me :). I asked the staff at the pet shop for another male but they lied to me and gave me a female who was already 2 weeks pregnant! (obviously I took the male to a nearby vet and had him castrated when I realised the error). every time I touched her or tried to go near her she bit me hard! she had her babies last week but she still bites. How can I stop her from biting me? when she bites she bites hard and draws blood. I've tried using a glove but she bites through it.I am only 16 years old and my parents don't really approve of my rat so I can only really let them out at night. She worked out how to open her cage and unless I put a lock on the on it she opens it and runs around my room. this helped a bit because I was able to clean out her cage and hold the babies but it is very difficult to get her back into her cage.
Your help will be much appreciated :)

Answer
Hi, pet shops do that a lot!
Anyway rats that bite are rare, but since she was pregnant that's a part of it.  It sounds like she was handled badly at the pet store. Patience is a key but I suggest trying to use yogurt on the glove so she starts to lick instead of bite. If you have or have been using a leather glove it works best, as it's pretty thick! So try using treats and wait until the babies are older as some of the aggression is from having babies. Once the babies get older and start to walk around and stuff the aggression might settle down a bit. Treats and baby food work as well.  Don't hold her yet because she's stressed. Give her plenty of food to keep her nurishments up high so the babies can have milk
Hope this helped
Emma
If you have any more questions feel free to ask!