Hopefully there isn't more rot than that. Not to scare you, but mine started with a spot under the helm pedestal, fixed that and a couple of years later the whole rear section under the rear seat was rotting, it turned into a full fledged stringer/floor job. I did about 1/2 of the work myself, having the more difficult parts done by the 'glass shop.
To fix, cut out the new pieces and soak all in CPES (see
http://www.rotdoc.com), be careful to wear a fume mask and gloves. You can coat the new pieces with epoxy on top of the CPES, but 2 coats of CPES is pretty good. I wound up ripping all the floor carpet out, had it re glassed and done in a non skid gelcoat. The carpet and unsealed holes was the cause of all the rot. All holes should be sealed with 3M 4200, and carpet has no place in an open boat.