You can't raise the bowl water level, unless the thing is misadjusted, which may not be the case. Where is the water level in the tank? Both the bowl and the tank fill at the same time, so assuming you have the right fill valve (very likely), if one is low, the other is. If the tank is at the proper level, then that's the level for the bowl, too. To test that, take a bucket of water and slowly pour it into the bowl. At some point, it won't go any higher. It is self regulating. After it reaches that point, after a minute or less, it should be at the full level, and shouldn't change.