Pertify or freeze and then break them apart with stonefist.

Spell Combos

Earthquake + Grease + Fireball + Walking Bomb should stymie most groups before they can do too much harm to your party.
A fire spell on Grease works great at lower levels or when you don’t have all kinds of time.
Glyph of Paralysis + Glyph of Repulsion causes an explosive effect that paralyzes those nearby.
Blizzard + Inferno + Tempest becomes Storm of the Century (spectacular electrical storm).
Cast Blizzard on a burning Grease slick to extinguish it.
Send a tank to draw all kinds of threat from a mob away from the party. Cast Force Field on the tank for immunity from all damage and then follow with Inferno to engulf the entire area. The enemies burn while fighting a tank that can’t die.
Drain Life and Mana Drain are twice as effective on a target with a Vulnerability Hex.
Cast Spell Might on yourself and then cast Animate Dead on a skeleton. This skeleton is much more powerful than the ordinary skeletons you can animate.
Cast Sleep on a target and then cast Horror on it. This inflicts massive spirit damage on the target, often killing many lesser foes outright. Those who survive emerge in a state of fear.
Immobilize a target with Cone of Cold or Petrify. When the target is in that vulnerable state, a critical hit from any weapon, a hit from the Stonefist spell, or the effects of the Crushing Prison spell will shatter it. (Bosses and lieutenants are highly resistant to this.)
Cast a Death Hex on a target and then cast a Death Cloud in its area. If the target is touched by the Death Cloud, it sustains massive spirit damage.

So I talked to her at the castle and then fought in the tower till the king and Duncan died.
Now I am in the small village (Forgot the name...)
Where is Wynne? Is the gone forever?
I know that she could join my party, but she didn't?
What now?

you meet her again at the mage tower