Year 12 repetition

I had moved to UK just last month and have joined a school here and am currently doing 4 A-level subjects. The school had started its session last year in September which means that I have to cope up with 3-months' work and I have my AS level examinations in 3 months. I don't know if I would be able to cope up with the work given that the fees of my school is quite expensive and keeping that in mind, I'll have to double check before considering to repeat my AS Level (Year 12).
What should I do?

Don't repeat the year
Do your best to do well in the AS exams. Prioritise the most important subjects YOU DO NOT NEED 4. Ask the school for some extra assistance. Work hard through the summer break to further catch up on anything you've missed. Resit AS exams if you need to (though unless you are taking international A levels you will probably find that they are linear courses where the AS don't count.)