Need help with AC/Gen setup for 37' Oday

[pogosmoke]

Looking at buying a 79 Oday 37 center cockpit. Would really like to put A/C on this, my child has a very serious heart defect and I would like to be able to keep him cool. It currently only has a 3 12 volt battery system no generator or ac. I know that I need some kind of generator and then would have to get an AC unit. I didnt see alot of places to put these items I know you can get different types etc. Whats the best setup without spending a ton of money. Im only paying around 25k for the boat so I would like the price to be relative to the purchase price. Also any links to sites etc would be appreciated.