If you are 'reasonably' sure you know which University and which course you want to go to/on then visit the University site and find out the Admissions requirements and any subject combinations prohibited.
This will help you focus on your January exams.
Post your responses in your blog under the heading 'University Requirements'.
You should ask a lot of questions here and here
I cannot help you if you will not help yourselves....
Also do some research and then do more research and more research and even more research and then reassure yourselves that only working your hardest AND also attending other activities - starting companies, attending evening classes, playing sports, doing community work - will all help you achieve your ultimate aim.