@ RP, you can't, running on a treadmill is the DULLEST thing I have ever done, it really REALLY is boring, it almost bores me to tears.
However, sometimes in the depths of winter, it's the lesser of two evils, although this year I am going to try and minimise it as much as possible.
I brought mine from Argos, it was £250 with a free cross trainer, so we have a little gym setup in the garage.
Last winter in was -8c at some points, and it didn't effect the treadmill, however, coming out of the garage after a run, into the cold temp is not pleasent at all, especially if it's raining/snowing.