Try to cut losses and money will be saved.
Don't engage enemies that are considerably stronger than yourself and try to do some quests that require no fighting, therefore giving you the experience needed for a couple level-ups.
There have been a couple threads so far dealing with money problems, look around and you'll find them. I think one of them was started by me; there I wondered whether money is in short supply in KB:AP, but it turned out this was the case only in the earlier stages in the game. Later, you'll be positively swimming in it!