You will need maths grade C or above for jobs and uni so definitely retake it.
Your level 3 course is only equal to one AS level so yes you did that but for a proper Level 3 course (ie equivalent to 3 a levels) you will definitely need more gcses. Also you will need 5 A*-Cs incl maths and English to get into 99% of universities anyway.
Also, you have to remember that universities are so oversubscribed that you need more than the bare minimum. You will be competing for places against people who have got 10 good GCSEs at the first attempt and good grades in their ASs and A levels (depending on which unis you apply to, obviously some are a lot more competitive and require much higher grades than others!) So you really shouldn't think 'oh, I have the bare minimum so that's fine.' You need to make your application as good as possible.
They probably haven't updated their website for all the 2011/12 courses yet, definitely go in and ask them.
As for science, did you enjoy humanities (history, geography, etc) more at school? Remember science is a HUGELY broad spectrum. This course is really broad, and if you did a gcse in psychology too then at university you could do any of these things (and more!):
Psychology
Biology
Chemistry
Physics
Oceanography
neuroscience
geology/earth sciences
pharmacology
forensic science
zoology/animal behaviour/conservation/animal welfare
ecology/plant conservation
sport science
renewable energy
environmental science/natural hazards
finance
accounting
business management/business studies
podiatry
radiography
occupational therapy
nursing
physiotherapy
engineering foundation year (you do 1 foundation year at uni then are usually guaranteed a place on the proper engineering degree at that uni)
And a whole host of other degrees that you don't need specific subjects for, including:
anthropology
sociology
geography (at some unis, you may need to take an A or AS level in geography alongside the L3 access course)
and many, many more courses.
(may be better doing the access to social science course for them)
The college also offers a pre-access to health and social care is that's more your thing.
http://wmc.ac.uk/courses/search-courses/?page=leaflet&mID=334000084352027Or a pre-access to humanities:
http://wmc.ac.uk/courses/search-courses/?page=leaflet&mID=334000020127345Whichever pre-access course you do, I think you can change subject area for the main (L3) access course anyway so it's not a binding decision!
Perhaps you could get some work experience? That could really help boost your confidence and help you work out what you want to do. Try getting a job too, because universities will be expecting mature students to have been in work. I know you haven't followed the traditional mature student route as you've been at college, but you want to be able to show them that you haven't spent 4 years just trying new qualifications until you find one you are good at, but that you've been developing other skills at the same time. Getting involved in sport and societies at college is also a great way to develop teamwork/communication skills, etc - maybe you could get involved in the college student council? You'll need something to talk about on your personal statement when you apply to unis. Doesn't have to be a lot, just something/things to show that you don't just sit in the library all day!