Even though it triumphantly backed Whitney Houston's rousing rendition of the national anthem at the Super Bowl last month, the Florida Orchestra is hardly having a banner year. The 86-member Tampa-based outfit is faced with a $2.7 million debt and wants a share of any profits from its Super Bowl performance. ''We're fighting for our survival,'' says acting executive director Kathryn Holm, adding that the strapped organization has yet to make its Jan. 31 payroll. The orchestra has received $80,000 in private and corporate donations since the Super Bowl and recently began talks with Arista Records, which last week issued CD, cassette, and video versions of the anthem (with profits earmarked for the American Red Cross Gulf Crisis Fund). The orchestra's original contract with the NFL, signed last December, didn't even mention subsequent releases. ''Nobody anticipated the reaction,'' Holm admits, ''but part of the anthem's impact came from the arrangement behind it, so we believe our musicians deserve some restitution.'' An Arista spokesperson would say only that the group ''will be compensated.''