Any moderate weakness in that area will probably re-emerge sooner (or later) - even if you push it down and epoxy it, it will still be weak and crack again when there is pressure on the fin. The surface repair only puts a stronger surface on the board, it doesnt make the foam under the board any stronger. The fin may wriggle around a bit even after the repair.
The usual method of repair is to cut out (drill out) the entire affected area (ie the plug hole plus the cracked bit), remove the plug, pour resin in the hole, stick the plug back in, then re-glass over the top. Others drill out the hole, fill it with resin then drill into the resin (as it if were the original board), insert the plug.
If you google 'FCS fin plug repair' you will get a few results eg
http://surfsource.net/repair/ (scroll down toward the bottom of the page). There are a few videos and stuff.
Is it hard? Guess it depends on how much you love the board and how much equipment you already own. It shouldnt take a surf shop too long to do it, they can drill and replace pretty quickly, its a common repair - maybe an hour of labour all up (but the repair will take much longer, given drying times etc). Shops in Australia charge around $80 (plus replacement plug if you need it), but it may be cheaper elsewhere (if you google 'fin plug repair' you may get some price lists from shops around your area).
Anyway - you will need to repair it, unless you decide to surf as a twinnie for a while.
Its a nice looking board. How long is it? I would be tempted to spring for some better fins, possibly a 2+1 set up (rear fin longer and some short side fins) - will loosen the board up quite a bit. But its a bit hard to tell how big your fins are at the moment, it might not be necessary.