Strategy needed for Invasion From The Unknown - ..New Knalga

[Kedari22]

I have tried the level Attack on New Knalga over 8 times using different strategy's but have never managed to survive past turn 10.
I have about 285 gold and am impossibly outnumbered.
I have some very good units to recall but would prefer not to lose them.
Can anyone give advice on this level? Please