Why is my cat is very aggressive?

I have a female (2 years old) blue Russian mix. I rescued her when she was stuck under bushes at 6 weeks old - which everybody knows it's way too early. But I had no choice. I fed her, the veterinarian approved the milk and already, she was destroying the nipples one after the other. She was fine until she reached 6 months old: she then started to urinate on the couch. I took me almost a year and a half to help her getting rid of her bad habit. At the mean time, when she reached more or less 10 months old, she started biting. Now, she bites, scratches and hisses. I really don't know what to do. When I got her, I already had a dog. She always loved and still loves the dog. She never was aggressive towards him. But with me, it's a challenge. Can someone please help? I love her dearly but I must say I have been thinking about almost giving her away - yet I am incapable of doing it. All advices are welcomed!