how long do I cook a 3.25 lb turkey breast and at what tempurture

I would suggest roasting it with salt and pepper at 375. To add some interesting flavors, bake it on a raft of sliced onions, carrots, celery, some garlic, and some fresh parsley if you have it. Roast the turkey until it reaches an internal temperature of 165. When you're done with the turkey, by all means make a great pot of stock from the skin and bones, and toss in the vegetables you roasted with it.