TBH, you're in the wrong class, and it's not like anyone can quickly fill in the gap in theory that you're missing.
Ring your teacher immediately and tell him. He may be able to transfer you to a more appropriate group, or if there's no other group then maybe he'll be able to get you a refund on your course fee. Don't wait until next week - ring him up now and get yourself to the right course for next week. Otherwise you'll basically have wasted your money.
thats really really helpful thanks very much for taking the time to post