How to fix a boiler that is not blowing enough air?
If the blower motor is actually a 1 HP motor it should be able to provide sufficient air delivery through the system. Do you know what speed the motor is utilizing, (most have 4 speeds). 

The coil design and the resistance of each coil will play a major roll in air flow as will the size of the supply and return ductwork. A lot of contractors use a high resistance figure when sizing ductwork in order to save a few dollars. 

This results in a lower delivered air flow, along with more air noise. With the information you have provided it will be very hard to offer any solutions. There are some pretty smart guys that monitor this site so more info is needed, such as the model number of the equipment including the heat coil specs, size of the supply and return duct work, type of filters used, etc. 

By the way, if the water delivery temperature was 160 degrees at the boiler, that is not very hot when trying to raise the house temperature quickly. You also need to check the temperature drop across the coil, the in and out temperature of the water and the air temperature increase across the coil. 

Raising the water temperature to say 180-200 degrees will greatly increase the output of the coil. The best answers would be provided by someone actually being at your location. 

Hope this helps.