Behind the handle bars, where it joins to the bike is called a stem. Remove the center allen key bolt that runs down the center tube. Lift the handle bars up an inch and tighten the allen key bolt again. Your handlebars will now be a little higher for you.

Another way is to loosen the clamp bolts that hold the handlebars to the stem. With riser bars, you can twist them in the same spot and this will angle them up a little. You will have to loosen the brake/gear levers and angle them down until they suit you.

If neither of these works you can buy stems which have varying heights and lengths.

Hope this helps, please vote for me.