I think you are saying that you took 2 A-levels.
You are normally expected to take three A-levels, so only having 2 will limit your options, regardless of the grades you get in them.
There is only one way to find out whether your chosen university will take you with 2 A-levels, one a C and one a D. Phone them and ask.
If there were special circumstances which led you to take fewer A-levels, the university may take this into consideration.
Different universities have different entry standards. If a university will accept your grades, you will have to decide whether to go to that university, or spend another year on A-levels and get into the university of your choice.
Whatever you do, talk to your school and talk to the universities. Don't limit yourself to one university.
Good luck.