the broken studs hammer out with a punch and a hammer. If you cant squeeze them behind the hub and bearing then you have to take the hub and bearing out. And unless you have an impact gun you'll never get the new ones in yourself. I would suggest taking it to a shop. To take the hub and bearing off there should be 4 bolts behind the unit holding it on. take those out and just pry/hammer the hub and bearing unit off. if its seized on there then good luck. but you shouldnt have to take the brake itself apart. I'm not 100% though cause I've never taken apart a celica at work, Sears Auto centers only charge like 20 bucks per stud replacement. hope this helps some.
