The A/C should have a drain tube. If water is leaking in from the A/C, check to make sure the drain tube isn't blocked.
From what I've read on these forums, most any panel can be replaced but some require a lot more work than others. It may be much less work to remove some of the "wrinkles" unless they are creases by using a dent puller. Take a look at this thread.
The area around your antenna may be fixable as well without replacing the panel.
Hopefully, others will chime in with their recommendations.