Gearbox Question

[Ginger Power]

We are having trouble winching down our catapult. We currently have a toughbox mini with 2 mini cims in it. We have the ability to put 2 cims in it but we are currently pretty far from the power we want to have for our catapult (like halfway or less to our goal and the motors stall out). We also have a reduction after the toughbox mini with a 19 tooth gear driving a 48 tooth gear. I wanted to know of any gearboxes that really gear the motor down and offer a lot more force. Also if the difference in power between cims and mini cims is significant enough could this solve our problem? If you could post a link to the website for the gearbox it would be greatly appreciated.