Why do you want to apply for medicine specifically? To do medicine at Manchester for example, you need AAA. You are 4 grades off that. Do you really think you can go up so significantly in one year and then more importantly maintain that level of performance over the 5 years of your course? Bear in mind that at the end of each year of your degree, if you don't make the grade you are out. There are lots of other jobs and roles both in and outside healthcare that fulfil the same role as a doctor utilising the skills they develop e.g. technical knowledge, team working, problem solving, working with the public, helping people.
Consider your next move very carefully and for what its worth, you are unlikely to be allowed to study in college even if they support a resit.