I'm afraid I don't know those brakes, you might find that there is a screw fitting up around the pivot area that allows you to adjust the reach to the brakes.

Regarding the bullhorns, it looks like those brakes already give you the "hoods" position which is a lot like a bullhorn position anyway. When you are on the hoods, you should be able to reach the lever with a couple of fingers and brake from there:



If you don't have confidence in that (I know that I don't!), you can get some "cross" levers that either run in-line with your existing brakes or replace them. The cross levers are small straight levers that fit on the centre section of the bar:



You don't actually need the bullhorn bars to get the same positions/braking, but obviously they have a certain "look" to them which you might prefer.