In terms of your degree choice, history offers good essay writing skills that are needed for Psychology whilst Biology offers the scientific foundations and an analytical mind set.
If you prefer Biology to History then that should be an important factor in your decision. A2 is more difficult than AS and carrying on with a subject you don't enjoy may become a chore. However, considering your grades, you may want to fact which subject you'll do better in, particularly if you're looking at a uni that requires the top grades.
Good luck!