I modified your table with a calculation for the operating current:
OHM'S LAW (The penalty for FORGETTING OHMS LAW is PIE in the EIR !)
P (Power in Watts) = I (Current in Amps) x E ( Voltage in Volts)= 337W = (I x 12V)=> I = 337W/12V=28.08A
CONCLUSION ? : YOU NEED A 30A MOTOR DRIVER.
This is a top of the line bidirectional uC controller compatible interface dc motor controller rated for 40A continuous.
Almost anything else you find will be a step down from this. Here's another good one.
http://www.robotshop.com/en/cytron-single-7--25v-40a-brushed-dc-motor-controller.html
You have to be careful ordering a motor controller online . Keep in mind, uC users are a minority. Most of the people don't want a uC interface (DIR/PWM inputs) . They want a potentiometer so you have to make sure you don't buy anything until you have seen a closeup photo of the PCB showing the DIR & PWM input silkscreening on the PCB or a datasheet that indicates it has those, otherwise you are going to wind up with a controller that only has the potentiometer control.
The ones I linked above have the uC inputs visable in the photos and diagrams.
Here's one that's less than $50
http://www.robotshop.com/en/30a-5-25v-single-brushed-dc-motor-driver.html
(save the photo and then open it and zoom in on the white 3-pin Molex male connector and you will see the pin labels are
GND
PWM
DIR
2013_Motor_Data_Table.xls (30 KB)