Your options are springs or making various trips to the coasts for beach/boat dives.
Springs:
Blue Spring - Orange City, about 40 mins on I-4 east (state park, $5 entrance i think)
Paradise Springs - Belleview/Ocala, about 1 hour on SR-408 to turnpike ($30 day)
Blue Grotto/Devils Den - Williston, about 70 mins on SR-408 to turnpike to US-27(?) ($30 each per day)
There are other springs more than 2 hours drive from Orlando
Saltwater dives:
Venice/Bradenton - shore dives, about 2.5 hours W on I-4, S on I-75, kind of rocky reefs and sharks teeth
New Smyrna - boat diving with Seadog Charters, ~1 hour drive E I-4, $65 for two tanker
SE Coast - boat and shore diving ~2.5-4 hours drive depending on what you are after, rates from $45-55 for a regular two tanker or free from the shore.
What takes your fancy, and would you like more info on??? Epcot is good, Becky and i enjoyed that last year, but pricey, big aquarium! I can provide links to info on some of those dives when i get back to my work computer that has them all saved, tomorrow!
Depending on your schedule to be in town, there are a few who might be able to dive with you, myself included, ask Murphdive286 and Baitedstorm when i hosted them when Murph was here on a conference. Also up for a dive, just need free time to do it in