I doubt that's included in the auction - it specifically says tube + psu.
Not like it's a big deal, a fountain pump and a bucket will be fine for shot runs. If you need anything more you can get a car heatercore for about $35 and it will have plenty of capacity to dissipate the heat generated from the laser.
The wattage is the nominal rating. Generally discharge tubes of any sort are tolerant of a reasonable variation, at least +/- 10%, but you want to keep it as close to nominal as you can.