I would try to find a decent condition EJ22 shortblock and swap it in. No need to rebuild it, or get fancy.
Since you are looking for more power, while you find an engine, send your camshafts to be reground by Delta Camshafts in Tacoma, Wa. I bet you have your cams before you have your engine.
EJ25 motors from a junkyard are about as expensive as on ebay, so no luck there. Your only hope is to find one on here or the other subaru boards.
Another option is to make a "frankenstein" motor using your current EJ22 heads and an EJ25 block and headgasket.
It really is up to you. I guess you need to ask yourself what amount of horsepower do you want? Since your motor is already fubar'd, you can spend as much or as little money as you want.