If AAA is the highest you will need, I would just resit 1 module and go for the A. Assuming you'll be taking other exams this year too, you would probably be better off with only 1 extra exam instead of 3, so that you can focus more on other subjects and give yourself a better chance of obtaining the AAA that you need.
If there's a chance you'll be applying for a course that needs A*AA, resitting 3 modules to get that A* might be a better choice if you're up for it, but I wouldn't recommend giving yourself all that extra work if you don't need to.