The best all season tire you can get would be Dunlop SP5000's. The snow rating on tirerack for these are pretty good considering these are a Z rated tire. I had these tires before and liked them a lot. MrFatBoy also has or had them before and he likes them, too I believe....

BUT, since your wife drives this car. I would invest in a dedicated set of snow tires/steelies and then get some summer only tires for the stock rims.