a good set of snow tires makes all the difference, don't go cheap.
i once had a set of nearly-bald summer tires and winter came too soon so i didn't swap them, i could barely get up a 5 degree sloped road, tires spinning like mad.
put on the snow tires and i'm passing everyone like i'm driving a tank with snow ski's and plowing through a foot of snow..... it makes such a huge difference. all season tires are bullshit, get some good snow tires and summer tires. and narrower tires will perform better in snow, i got 205/55/16's on the stock rims for mine.... they're cheaper too...
i also had about 150lb of car audio in the hatch, so that might have helped too