The fork is probably ruined, just be prepared to have to replace it. That is supposed to be a press fit and if it is loose and ridden loose, it is probably done.
Ok, now that you are prepared to replace it, lets try and fix it: You can try Polish knurling. Just take a punch or sharp cold chisel and go around the surface where race is supposed to fit and strike it making dents, the sides of the dents will raise up slightly making the diameter larger. Since you are effectively cold forging the aluminum, it might hold up. At the same time you reinstall the race you can apply a strong 2 part epoxy like JB Weld or PC7. Cross your fingers, allow the epoxy to cure thoroughly, and ride it.