I don't know what brand of charger to use, but I can make suggestions on how you can get the most charge out of the battery.
Pop the ventilation caps, be careful of the acid as it will burn your skin, and make sure that the cells are completely covered with water, and put the caps back on. When you're charging it, make sure that it is trickle charge, 2 amps or something like that on 12 volts and I would say leave it charging overnight.