On average you want an MCA of 4700+ to be competitive. The majority of HS schools will not let students with a C or higher retake classes. Since you are a Senior, your current grades are going to be reported for the application which closes on November 30th, so SLO will not see your repeat grades even if you are allowed to retake those courses and they will not be considered in the application review. It is what it is at this point. Apply, hope for the best and make sure you have several safety schools on your list.