Oh I'm sure there'll be plenty more questions! It's only natural so please keep them coming - people on here generally are very helpful and eager to impart their wisdom/experience/opinions!!
I'm afraid "working" will be all but impossible as even though they wouldn't pay you, they would still have to insure you to be legal. That last point is key and I'm sure many types in Spain would employ you for nothing and take the risk that you wouldn't have an accident or get an inspector visiting - but you are exposed and your record would be tarnished becuase of it if you plan to come back. I would suggest simply staying away from strong expat zones - so that you will HAVE to speak Spanish, albeit starting with very pidgeon Spanish - but you will pick it up in that scenario. Don't kid yourself that if you mix with expats you will learn the language, because you're in Spain. You won't. The only way to force it in a short period that is six months is to have to in everyday life. Try and find, for example, a bar or bars, places that Spanish frequent and not the bars/places expats go to. This will allow you to mix with the locals more.
I could suggest that you approach your local ayuntamiento who would hopefully have a list of ONGs (organizaciones non-gubermentales - which are in effect charities) whom you could approach to work on a volunteer basis, but even that may not be possible without NIE etc. Might be worth a shot, though.
Get yourself onto a course at your local college asap if possible - I don't recomment really the online stuff or CDs. If you have Sky, watch TVE, obtain magazines, articles (in your area of interest) and familiarise yourself with Spanish by doing things like Google.es and clicking on "noticias" which is news. This if nothing else will help you if you're doing any sort of course to see how your understanding is going and to broaden your vocab.
Not sure about that area you're going to - so any questions on location I'm sure others can advise you on.
Tallulah.x