It will operate in much lower temps. Anything down to the 20's F and you should be fine. When it gets very cold, the most likely effects are a stalled hard drive due to the fluid in the bearing becoming viscous and the screen will be quite dim until it warms up.
I recommend you try and see how it works before doing some kind of upgrade. You may be fine.
As for the heater vent, you should be okay if there is space around it for air flow.