My advice would be threefold. First, check out some reviews and see what is available at tirerack.com, and get an idea of cost... etc. Second, know what the universal tire grading system (it's a number follwed by two letters on the side of every tire. Don't get anything that isn't "a" and "b" or better for traction and temp. The number relates to how long the tire will wear, so consider paying extra to get something in the 600's if you plan on keeping the car for awhile. Third, don't be tempted to get light truck tires, rather stick with passenger car tires.
I have a Highlander that can use the same size tire. Most people at the forum I live on for that vehicle prefer the Michelin LTX or Crossterrains, though they are expensive. The Yokohama Geolandar H/T-S G051 also gets some good reviews.