I like most of Douglas Schroeder's advice. Without knowing how good your source is (if it is not great you should upgrade it first), swapping your HK for a high-quality integrated would give you the best sound value right now IMHO. As for buying a power amp now, I would much rather have a good preamp and an ordinary amp to listen to while I saved, than have the reverse. With a good integrated you get both and you save on interconnects as well.
However unlike Douglas, if I were you I wouldn't change my present speakers until the end of the upgrade cycle. This is because each time you improve what you feed them, they will sound better.
However unlike Douglas, if I were you I wouldn't change my present speakers until the end of the upgrade cycle. This is because each time you improve what you feed them, they will sound better.