You could take it apart and see what limits the lock, maybe you could think of an solution to get more wheel lock, but you won't get more than about 350° wheel lock (overall, about 175° to each side) with this method.
And it will be almost sure that you will need to fit an other potentiometer to your wheel.
But such mods are not very easy to make, and often aren't possible at all.
Would be better to buy a different wheel