New problems after the -35 degree weather

Hello, I just joined! I have a couple problems with my 2000 Pontiac Sunfire, 2.2L with 110,000 kms. I am losing about 50 kms to the quarter tank of gas, and I can smell what I thought was oil when I drive. My fluid levels have not dropped at all and I can't see any puddles under the car. There is no huge cloud of smoke or anything, it starts fine, and still has normal power. It's best on the highway. The smell seems to be coming from around the battery and wiper fluid container (thats where I can trace it to). When I turn on my heat, the oil temperature gets a few notches warmer, and cools down within about 3 minutes of turning off the heat. Also my rear defroster completely wont work, changed the fuse, no lines in the window are broken, and power is getting back there. Thanks for any suggestions anyone can offer.

Not to suprised with the drop in milage with the cool weather. Do you have winter fuel there? Since the switch to it here (in Nov, Dec whenever they do it) Our vehicles have been dropping in milage also. Checked tire pressure lately?

Yup, just checked the pressure after my tires were switched up. The mileage loss was not this huge last year, but my big concern was if it was related to the smell (gas leak) i don't need my car exploding in time for my christmas credit card bill :P Is there anything in the cooling system (a hose) that could generate this sort of smell....without losing fluids?? Thanks, Merry Christmas!

I am not sure, but there may be a cotainer near the front which has something to do with gas fumes with it gets clogged. I know my Sunbird has one.