As ROD says you need to know the wattage, the resistor is the easy part, but get one too weak, wattage wise and it will burn out.
When you know the wattage look for CERAMIC resistors, if you get stuck pm me with the details, they're a only a few £'s, so no biggee.
They may well be rated at 500V or more but this is as said irrelevant.
tabetha