You can't modify it. I'm guessing this came off ebay in which case it is probably putting out a HUGE amount of dangerous invisible IR light, so you need to be extra careful using it.
Twist the pot clockwise.I can't say how much.If it has APC, you need to disable that first. :-/ And I also can't say for sure if this will work/not work/totally screw up your laser.Maybe the crystals are barely handeling it as it is, so turning it up will only give you more IR or even totaly screw up the crystals(and maybe spitting out even more IR, with no green).
Well I'm guessing that the pump diode is a closed can (windowless or not, don't know cause I don't have a dx laser), and that APC works using the photosensor inside the can, so if you just unsolder the 3rd pin on the diode it should stop working.Maybe this alone is going to give you a power boost, or make the laser stop working at all.....just guessing here.