is there any software can convert s700 themes to k700 themes?

Not that i know of, other then a themer (which isn't a tool but a person).

This tutorial may provide some help though:

http://www.valhala.be/Goodies/tut-converting-themes

so i must use the photoshop :S

it takes long time

thanx vinnieza

You're better off finding the same wallpaper and starting from scratch, will be much faster than resizing everything to fit.