Af Hall,
If I'm understanding you correctly, your heater died... you currently have a 800watt heater, but don't want to use it?
For a "for now" fix, put the 800 watt heater into your sump, until you purchase what you will end up buying. It will be pleanty to heat your tank for you without worrying about wrapping your tank in an electric blanket or any of those other emergency needs.
Once your new heater arrives, simply swap out the 800watt for the new one, and you again have the 800 for a spare.
As for what brand of heaters to use, I like the Finex heaters, but there are several good brands out there that I have seen other's here talk about... just use the "SEARCH" feature here, and type in "Heater"... and see what comes up.