OP,

Keeping the Compact and swapping the chainring to a 34t is a lot cheaper than buying a whole new Crank, Bottom Bracket, and Front Der. Also, you'd need a new shifter. (Big Bucks!!!)

So, I would recommend keeping the CT crank for now.

I would also try the 34t ring first to see if you like it. You may not need to get a bigger cassette if it is good enough. A 34-27 low end is pretty good for most climbing, so it may do the trick.

If you are still having trouble, I would almost suggest then going to an 11-32/34t Mountain cassette, and swap out your 105 Rear Der with a Long cage. A long cage 105 Rear der is only about $45 on sale, still alot cheaper and lighter than changing the whole crank to a triple.