Many years ago I did something similar with my first car (an old VW Rabbit...). At that time Canadian Tire sold a rubber expansion plug that did the job. Basically there was a "plunger" type tool that would force the rubber plug to shrink in diameter as you jammed it into the hole... and when you yanked the plunger out the rubber would expand back to it's original shape (you would basically stretch the rubber by pressing on the tool... this would reduce the diameter... when you removed the tool the plug would return to it's original larger size). Did the job until I could work on the car in warmer weather. I think it's likely that other auto parts shops might have something like this. Lordco?? etc...

This one (bottom of the page) is sort of what I recall (it was twenty five years ago... lol): http://www.popularmechanics.com/cars/how-to/maintenance/1272546?page=3