Biology is great, especially if you enjoy it, taking that will really help you when you go onto uni as every accredited psychology course has to include biology elements. Psychology of course is great.
Don't worry about not doing maths, a lot of courses now use computer based programs to work out the maths. I got a B at GCSE and find the stats at uni fine. I attempted maths a level and only got a D at AS then dropped it though because it is a big leap up from GCSE.
In terms of another one sociology would be best for psychology out of your choices, but a lot of that will overlap with your psychology course so it's not necessary and if you like another subject better I'd do that. If you like English I'd recommend English Language as it often has child development of language in it that came in very useful for me when lectures started talking about phonetics, pragmatics, syntax etc I wouldn't of had a clue if I hadn't done that course.