What are enchanting level effects?

Possible Duplicate:
Disenchanting diminished return

I'm new at enchanting... And don't understand (yet) the mechanics very well.

I found an axe with 10 fire damage. As I'm a sword specialist, I destroyed it to learn the enchant. And when I try to enchant my sword, it's only 1 fire damage...

I'm level 20 at enchanting. Should I increase my level to have a greater fire damage value ? Let's say I'm level 100, will the fire damage be greater than 10 ?

Is there any "quick tip" to get an approximate of the final value from initial enchant value and level ?