From a quick look, using the same site is an option, but to grow the seating bowl in any significant capacity, I don't think it can be done where the ballpark is sitting right now. The first base side of the ballpark is only
± 12' from the sidewalk on Tech Drive. There is plenty of room on the homeplate side,
± 92', and the third base side,
± 87'. In theory, if you started from scratch, you could rotate the ballpark about 5 degrees and get more room on all three sides to increase the seating capacity of the main seating bowl. This would shorten the left field foul line a few feet, but would allow you to deepen the right field corner as well.
The damage to the roof could have impacted the stability of the seating bowl structure below it. It will hall have to be thoroughly tested. There really isn't much use in trying to "fix" concrete structure. If the damage is extensive enough, it may be cheaper to rip it down and start over than trying to fix the damage.