ghandee, Maybe the translation, but I'm a little confused as you write that "..new bars is not an option." I'll take that to mean you want to keep your stem and find handle bars with a 25.4/26 mm clamping area, is this right?
If you're going to use ergopower shifter/brake levers you'll want to find handle bars with a double groove for cable routing in a width that's comfortable.
Brad