My cat is terrified of the new cat

I took in a stray cat and my cat is absolutely terrified of her. Im not entirely sure what to do. She hisses and cries whenever she sees her. The stray just ignores her. I really need them to get along because in a couple of days Im going to have to go to work and I dont want to lock them up in a room...
How do I get them to get along!

always make sure that you give her as much attention if not more, just to show her she wasn't being replaced. Eventually they will get used to each other. Even if they aren't ever good 'friends' I don't think that she will ever attack her, viciously anyway.

My son was reading some good advice about this. The first stage was to keep them shut in separate rooms, I'm afraid. The idea was to let one out round the house at a time, so that they get used to the scent of each other and become familiar with the idea that another cat is around. Stroke one cat and then go to the room and stroke the other, to send the message that you accept the scent of both cats. Then gradually begin to let them share the same space. It sounds like hard work, I'm afraid.

My son was reading some good advice about this. The first stage was to keep them shut in separate rooms, I'm afraid. The idea was to let one out round the house at a time, so that they get used to the scent of each other and become familiar with the idea that another cat is around. Stroke one cat and then go to the room and stroke the other, to send the message that you accept the scent of both cats. Then gradually begin to let them share the same space. It sounds like hard work, I'm afraid.

The same thing happened to me, I had the stray for about 3 months, tried everything I could to help my first cat get used to him, but the stray attacked her so I had to take him to the animal shelter before he hurt her any more