Need help with some electronics.

[GnarKill]

im rockin a rooster crawler brushed with a Low Bucks Racing 55T Dual Ball Bearing Brushed Motor in my scx10 with the stock pinion (20) and the stock trans spur (87) and it barely goes faster than walking speed. i would like as much torque as i can reasonable get while still having enough wheel speed to sorta bounce the front end around if im stuck, if that makes any sense. do i have to switch to lipos to get higher current from the batteries themselves for more wheel speed or is it more complex like i need a 2 speed trans. im still trying to learn the different techniques to building these but it's hard to search for the right thing. any help will be rewarded with vergins in the afterlife, thank you.