MTX MTA 250

Hello to all, I'm a nube so please help. I need to replace a resistor in my MTX MTA 250 Terminator amp. The value is 270 ohm/5%, but I'm not sure what wattage to use. The one in my amp is baby blue in color with the bands of red,violet, brown and gold. I could not match this up at the local RadioShack store. Anyone know where I can find the right chip? I think I only need one. Thanks to all.