A kolsch is just a very light lager, fermented with a different yeast. If you have a favourite pale (European style) lager that is low in bitterness, use that kit, but ferment it with one of the liquid Kolsch yeasts from Wyeast or Whitelabs. If you don't use the right yeast... its just not a kolsch.
Ferment it at 14-16C which depending on where you are, is probably what you will get from ambient this time of year. I'm doing a kolsch ATM and its just at room temp in the spare room (Melbourne).
You will find that the real kolsch yeasts just hate to settle out though... so its not a style I would try unless you can either filter the beer, or you are willing to fine it and lager it for quite a long time till it clears. The yeast tastes funky so you cant get away with it being cloudy.
Mind you, you can probably get pretty close with easier to handle yeast, but I wouldn't know which one to use, and it wont be quite the same as the genuine article.
Thirsty