Civic EG

So i started to take out my old alternator and got everything off except for one bolt at the bottom which is holding it on the bracket. It wont come out and its starting to strip.
Here is a pic

and this is what it looks like out, Forward to 8:48
http://www.youtube.com/watch?v=9M4lB8n6Vmk

Two questions:
1. whats the easiest way to get it out?
2. does anyone know what size it is and where i can get one?

All help is greatly appreciated

Looks like you've already used PB blaster on it... did you try heating it up a couple of times? I'd go to the honda dealer for another bolt and/or nut if this one gets messed up.

alright so i finally managed to get the nut off! I had to use a nut splitter and drill it and all sorts of stuff lol.
Anyways, now that the alternator is changed my car is idling at 2k rpm..Ive read that it could be vacuum lines (checked that), or throttle cable (checked that too), or the ecu needs to be reset and kind of "broken back in". I plan on resetting the ecu tomm but i was wondering if anyone else has experienced this problem?