In general, it should be possible to straighten the frame (perhaps using a tool like Cudak's Park frame straightener), but what concerns me in your case is that the upper head lug appears to have separated from the top tube:
This raises concerns for the integrity of the joint itself, and may mean a proper fix will cost more than the bike is worth.
There are some decent components on the bike; you might do well to transfer what you can to a different frame.