Both are counted in AADSAS, and averaged. What were the original grades? Lower than a C, you must retake for dschools to count them. If we're talking B's, then do not retake. Adcoms know you're trying to boost the gpa. It's also a waste of money in that instance. Instead, take upper division science courses in the same vein of study to show mastery of material.
Apply first, no later than July. Take the DAT no later than August. You will have the opportunity to show them your in-progress and planned coursework during the academic update period for AADSAS.
Do not hold up your application because of your DAT score. It takes AADSAS at least a month to verify your grades, during which time you can continue preparing for the DAT.