Honestly its not that hard to do at all if you make sure the main breaker in the panel is turned off before wiring up the breaker and installing the breaker into the panel. Just be sure you run the right size wire to support that load safely(#10 wire will support 30amp) and I would pull a 10/3 run(4 #10 wires which would be 2 hots, a neutral and a bare ground) if you are putting this in a 240v/30amp dryer outlet.
I went down this road when an electrician quoted me over $2k to give me the wiring service I needed from my home to my shed less than 25ft from my main home panel. After I stopped choking once I got the quote, I said heck no, I can do this myself.
I myself was a 100% electric newbie about 4 months ago when I started my journey to do this myself and had the same concerns as you did, but picked up a few well known and cheap wiring/electrical books and read up on some others journeys with e-brewing on HBT and I was able to not only install that breaker myself, but to run a buried 4 wire feeder 240v 50Amp (feeder run was approx 25 ft from house to shed) to an external building(even dug that damn trench myself), install an additional sub-panel in the outside shed which included service for the 240v 30amp outlet along with a few other circuits for lights,etc., wire the whole building up along with the other outlets going into the building for TV's, lights, etc. and it all worked(much to my surprise) like a charm.
Unless you are having to fish wire through walls to beef up the wire size needed to support the load(and even this is not too bad), you can do this yourself and save some cash for other stuff like brewing equipment/supplies..Grab a copy of this book which is a light read(HDepot or Lowes usually has it for like $6):
http://www.amazon.com/dp/097929455X/?tag=skimlinks_replacement-20
If you still feel uncomfortable about doing it after reading it, then hire someone..There are also some GREAT YouTube videos out there on adding that 240v service to your existing home panel that show you how its done..its honestly very easy to do.
If you are just replacing an existing dual pole 30amp 240v breaker for a GFCI dual pole 30amp breaker, its a 5 min swap out. Again..make sure you turn the main panel OFF and you will need to move the neutral on the outlet circuit to the GFCI breaker and the white pigtail wire from the new GFCI breaker goes to the neutral bus in the panel. Also FYI as it confused me when I first saw this, the neutral and ground bus bars are shared in a main house panel...this is not the case in a sub-panel.
Sorry to be long winded but want to be sure that you know from someone who was where you were that its not as daunting nor scary a task as you think it is. Just read up on it some and you can do it and keep that $$$ in your pocket.