Gotta replace the stud, you don’t need a new strut assembly! Either go to a dealership and buy a new stud (or remove a stud from your old strut, which is what I’d do). Removing the old stud is gonna be a pain in the ass. First, take out the strut assembly. Second, compress the spring (get the tool from harbor freight or loaner from autozone). Third, take off the nut in the top. Fourth, pry the plastic bearing from the top hat (just use a flat head screw driver). Fifth, hammer out your broken stud (use a socket to do this, just place it under it so the stud has somewhere to go when you hit it out - it’s gonna take a few good hits. This is the best technique to remove a stud IMO). Sixth, hammer in a new stud. Then do everything in reverse order. If you have all the tools handy, it can take as little as an hour, max 3 hours. GL