A rear sway bar is far more important on a front wheel drive car, but both should be used on a street driven car.
Any sway bars will make a difference comparing to nothing. I would look into aftermarket bars, Eibach, Neuspeed, Suspension Techniques, Hotchkis.
look here -
http://www.beaksproducts.com/Products.htm
Stock front with a larger sway works best for me. If you use a larger rear sway I highly rec. beaks reinforcement kits. a rear lower tie bar is also a good idea with a larger rear sway.