Zip 32321 is in Liberty County which is the Panama City DMA. There are no DirecTV locals either HD or SD available in that particular DMA. That means the SL3 is probably the dish to choose if you want HD, if Panama City ever gets locals they will almost certainly be from either the 99 or 103 slot which means the SL3 is enough.
If you want the ethnic package, or the Hope channel, they are from 119 which means you would need the SL5.
If DirecTV does the dish upgrade, it will almost certainly not be SWM because policy is not to use SWM on upgrades. If you are buying the dish yourself I strongly recommend you get a dish with an SWM LNB as "future protection". Prices for complete SL3 SWM setups from ebay suppliers are at good prices. Although you don't have DVRs right now, you might get them in the future and if you ever decide to go to MRV (multi-room viewing) you will need SWM to use DirecTV's new technology. The H20s won't work with MRV however since they don't have ethernet connections.