Lowes, Ace, and Home Depot all have good selections of metric fasteners. You'll need to bring in one with the same threads as the hole to compare.
If you attempt an Easy Out, do not break it off. If that happens your only option is welding a nut onto the bolt, the Easy Out is too hard to drill through.
Deleted the sway bar for now. Will fix it when i can just drop in a new subframe. Everything on the rear crossmember is just so rusted its time for a new one. Will post a build thread when i drop it out.