There are 3 or 4 Asian markets in Tallahassee. You might want to Google the info to get a complete list. We have very few compared to California.
Speaking from experience and from my observations of the number of Asian people shopping in the store, I suggest you try Mikes Seafood and Oriental Market at 1214 Capital Cir SE.
Also, Southern Seafood, 1415 Timberlane Rd, seems to have a large following of Asian customers ( a Japanese restaurant, Kitcho, is right next door ).
I am not familiar with any restaurants who routinely serve blue crab, but I know that some do on a seasonal basis. Someone else may be able to help you on that one.
Good luck on your move!