Thanks for the question!
If you want to stick to the Pop Century, I would recommend calling in to the Disney Reservation line and making sure that they have a room preference listed for you. It does not secure a room for you, but it helps them when they allocate rooms to reservations. Also consider calling the actual resort about 9 or 10 days out, and do the same. The phone number for the Pop is 407-938-4000. Ask for a room that does not face a pool and you are well on your way to some quieter times.
As for upgrading, I don't know if that would be necessary. Noise can be a problem in any resort, and moving up would not remove that problem. However, if you are thinking of moving to a Moderate, I can tell you that any of them would be great. Select based on preferred theming, but if I had to choose, I would say that
Caribbean Beach or
Port Orleans Riverside might be best, based on children's ages. Coronado Springs can get noisy due to the convention crowd, and Port Orleans French Quarter is not as fun for younger kids as the Riverside.