The admissions board will look at college grades very carefully. What they are looking for is a curriculum that mirrors that of the first year at the academy- therefore, a minimum of 16 credits, calculus [or pre-calc if there has been no foundation on the HS level], english literature, american history, and chemistry with a lab.
Grades of 3.0 and better will be viewed favorably.
They will also want to see that some sort of physical activity has continued while in college. Leadership remains a plus, however if it has been strongly demonstrated in high school that is acceptable.
Two other items for the check box: first, keep in mind that approx 30% of the incoming class for any given year has post-high school education under their belts. Second, that a second application does speak to motivation and desire.
Best of luck!