Transair do the Florida and Bahamas sectionals (page 30 of Xmas catalogue).
18 months ago I got California/Nevada sectionals online from Sporty's in germany: very quick arrived in 48 hours but I'm not sure if German branch of sporty's is still functioning.
I'd echo previous advice of getting them as long as possible before you go to US and study 'em thoroughly: they're very different from our charts!
Safe flying