You can write a formula to award additional points for players with more than 3 hits, but Formulas are "per-person" and cannot compare values against other players. Therefore, you can't use the formula to award points to only a single player based on their number of hits - the formula will award those points to any (and all) players who have the qualifying number of hits.
I can't think of any way to do this automatically; I think you'll have to do it manually. You can either create a prize for this (set the recipient to "manual" and then use the Override section to award the prize once you know who will win it), or you can simply adjust the recipient's points (edit the player on the Players tab and enter the adjustment there).