Amazon.com SET of bottom brackets.
A professional would probably recommend replacing the whole door. I honestly would as well.
But these brackets should work fine, they are a slightly different design overall but they still have the cable mounts outside of the track and fit on your 2" track.
If you have the torsion style springs above the door or rear mounted above the door make sure you bar the springs to keep them from turning and make sure you use something to hold the door up while youre working to ensure it doesnt fall(vice grips on the track on the lower section of the next wheel up will usually do the trick.
New lags should be installed in place of any screws that do not line up with current carriage bolts on door.
If your springs run parallel with the track and are the extension style its honestly a bit easier to undo the tension when you have the door open and there will be no potential energy there.
If you have any questions fire away though and if there is questions post more pictures of the springs, brackets, full door when closed including springs.
