Just happened to see your thread . . .
I recommend you use a "film" resistor since they are very stable in high temp situations. Here's link to "Mouser" . . they have
everything electronic and they're are cheap!
This is 68 ohm, 0.5watt, 1% metal film resistor that costs $.13 each.
http://www.mouser.com/ProductDetail/Xicon/273-68-RC/?qs=sGAEpiMZZMtG0KNrPCHnjfSDAuUPXjOYkZ2FglWjjnc%3d
At that price, you could buy a few at different wattage, say 1W, 2W, etc.
Here's a 1W version, 1% version; price is $0.70 each:
http://www.mouser.com/ProductDetail/Vishay-Dale/CPF168R000FKB14/?qs=sGAEpiMZZMu61qfTUdNhG33BaVfMIgUsb7yqqMn1dBM%3d
Here's a 2W, 5% version; cost is $0.32 each:
http://www.mouser.com/ProductDetail/Vishay-BC-Components/PR02000206809JR500/?qs=sGAEpiMZZMu61qfTUdNhG%2f4r7Iw6CIkyvLyi6YDfBsU%3d
If this is a "current sense" resistor and it's "5W", then I doubt that it's "68 ohms"; most likely it's a "0.68 ohm". .
Here's a 0.68 ohm, 5W, axial resistor: cost is $1.20 each:
http://www.mouser.com/ProductDetail/Panasonic/ERX-5SJR68/?qs=ykEKLGTiBczSOwfH5bnJqw%3d%3d