Broke my bolt

[apaz]

So... the title sums it up, but here's some more detail. A while back I had a leaky situation going on with the cylinder head. I got a flat tire in the middle of last winter and put her away to work on till this summer. I have her back together but I still have that leak. With the awesome suggestions of you guys (and gals), I torqued the bolts down and got a bit over zealous on one of them and broke it. Now I guess it's hard to deny that I have a leak.

Anyways, I'm wondering if anyone knows about getting the bolts that go there. I am checking out BikeBandit, but a little unsure about which one I should be getting.

What is the level of difficulty for the job? Can it be done in a weekend? Can i get the head off without taking out the engine? I know I need to replace the gasket, but is there anything else that I should replace while I'm in there? Maybe a list of other gaskets and stuff?

Sorry if I'm asking questions that have already been asked. I'm attaching pictures of the area I'm focusing on.

You guys have been awesome in the past and thank you in advance.

Armando

QUICK EDIT: Just chatted with Bike Bandit and they say that it's #12, and hurray for me, #12 has been discontinued. Anyone know of another good possible place to find that bolt? Thanks.