Playing Ciri, I keep on dying despite her teleporting ability.
Are there any other skills that can be used on PC?
In the Kaer Morhen battle she had an emulet but it does not work here.
Does the strong attack key work for her or any other key for that matter.
How does she regain health?
I don't recall having any problems in my first play through but with NG+ I
find it impossible, even on a low level.
In the entire battle of Kaer Morhen I only died once but so far about a dozen times here.

The key is to stay away from the crones; hit and run. Use Ciri's abilities. Speed and Blink. Keep at it, but be patient, because she's not close-in melee fighter.

I know. The problem is that the fight never ends as the blows I inflict do absolutely no damage to their health.

Someone said holding down the strong attack key that works for Geralt works for Ciri.
Someone else said Geralt's cast sign key activates a charge attack.
To hold down any of these keys I need three hands as they are at the opposite end of the keyboard
to Ciri's movement / teleport keys.

Ciri's Blink ability is a charged ability. You use the 'Q' key. You have to hold it to charge the ability, and the longer you hold it, the more powerful the attack.

@Boeriemore

If you want to see which special abilites Ciri has then press "TAB" (ingame).

http://www.mediafire.com/view/nfyq71qkl2qkk8d/Ciri_Special_Attacks.jpg

1. The "Magic Amulet" doesn't work in this situation.

2. Blink

If you hold "Q" you will see a circle with growing radius. If you activate the attack then all foes in the circle will be attacked - lightning-fast. Often Ciri is able to perform a backside attack afterwards.

https://www.youtube.com/watch?v=WJ6qulex71Q

3. Charge

The very strong and fast attack "Charge" will be initiated if you press and hold "Shift":

https://www.youtube.com/watch?v=2ES3axlhFbE

(Both very short videos in slow motion.)

In both cases you may trigger the attack by releasing the corresponding buttons.

I changed the difficulty level to low then killed them. I then returned it to normal and killed Imlerith easily.