The maths A-level assumes your GCSE knowledge to be perfect. There will be some familiar bits at the start, like quadratics and simultaneous equations, equations of straight lines, the simpler bits of vectors, equations of circles (although that is expanded on a bit) but... that's about it.
You will usually have to take applied modules as well, like statistics and mechanics, but that depends on your exam board.
Speaking of which, do you know which exam board is offered by your school for A-level maths?