weak screen washer pump

Just a quick question has anyone uprated their washer pump , is this even possible or has mine just gone week over time .
Ive blown it out with an air line so there are no blockages and cleaned the jets with a needle .

Ill be honest it works to clean the screen but I want to be able to blast the car behind when im being tailgated on the motor way .

I hope no one thinks this is a bad thing but im sick of drivers trying to get into my boot/trunk when there is two dozen cars in front of me all jostling for position all just trying to get home, some even resorting to undertaking .

A lot of the time now I just stay in the slow lane at busy times and watch how close people drive to each other and see 4 cars in the fast lane in the space of 2, often in the dark and when its raining.