vincemoran

So, my car used to have this overheating issue that's beginning to occur again. I thought it just wasn't ran enough (I recently purchased my IS300 a little over a month ago), or at least that's what my Dad had told me when he's brought the car from an Auto Auction. He would tell me that when the engine overheats, to turn on the heater and run it on high. And I've never had a problem running the heater. At all, actually.. And now, with the temperature being a surprising 18 degrees in Denton, TX., I haven't had a problem with my heater turning on until now. My A/C / Heater isn't producing any kind of heat. It's producing air about as cold as it is outside. Is there anything else I can do to fix this? Is there something I'm missing? Anything I should have checked out? Because I can't go more than a mile without the Temperature Gauge going above red.