I would try to find a shop that has done pervious fiberglass repairs on motorhomes or trailers. Typically these panels are a fiberglass sheet on the exterior and a thin wood panel on the inside with foam sandwiched in between. It can be repaired but a general body shop will probably only have experience in repairing by slapping fiberglass repair on the exterior. They might try to fill the hole with a material that could destroy the foam which also serves as a structual function. (ever seen what gas does to styrofoam?)
Water is going to you immediate danger to additional damage. Eternabond tape will seal it up if you want to make a temp repair, but it will be tough to remove in order for a shop to estimate it.
Good luck and sorry for the mishap.