<p>You need to show you are an excellent student in all the subjects that count. That means perfection in your current maths and science courses. ECs don’t usually count for UK admissions unless they are specifically related to your course of study. Therefore if you have any computer related EC, cultivate this (but not if it leads to neglecting your studies). There must be a reason you want to devote three years of your life to studying only computer science on a tough course (and I hope it’s not because you think it will be easy)! You need to find some way to demonstrate you are extremely academic and focussed, which does not come across from the information you have given us.</p>
<p>There is no concept of transfer. You would have to apply for first year entry. You can usually only apply to Oxford or Cambridge for undergraduate in one year, not both.</p>
<p>Mature (over 21) students and those who have not finished high school often take an access course. This is a one year refresher course in various subjects offered by many UK universities. I don’t know much about these courses but it may be worth researching as completing one would likely increase your chances of admission at any UK uni.</p>
<p>Finally, be aware you are extremely unlikely to get any form of financial aid. The UK business model is that foreign students subsidise the home students.</p>
<p>I recommend you Google the student room for a UK board similar to this.</p>