I've seen this before on a WRX. Take the lateral link off with the bolt seized to it. Cut off the bolt. Press out the bushing and what's left of the bolt. Replace bushing, buy a new bolt. You can also try to just press out the bolt, but good luck with that. I did manage to press out a seized one on a trailing arm with about 25 tons of pressure.
Option 2 is to buy a new bolt and just get a new lateral link, they are cheap.