As far as programming goes, pretty much anything that can be done with Game Maker 7, I can do, and I know a bit of Python. Formal logic-wise, I have Greg Restall's "Introduction to..." (I have a B.A. in Philosophy, on of the modules of which was formal logic). Thank you for the advice.
You should be able to cope with coq, I think. I think just going up to the logic section would be useful, the rest is only really relevant for heavy program proving. Let us know how you get on and what you find useful.
If you are in London I can lend you Conceptual Mathematics, if you want.
This will not be a long post; I have a simple question to ask: if you wanted to educate yourself to graduate level in mathematics, but didn't actually want to go to university, what would you do? I would ask for text-book recommendations, but I don't want to limit your responses (however, bear in mind that the wikipedia articles on, say, cardinality or well-ordering go over my head – they may skim my hairline, but over they go). Also bear in mind that while I personally have A-levels (British qualifications) in both Maths and Further Maths (which is to say, I know some calculus at least), there are probably plenty of people on lesswrong who don't and who desire the same information – so assume as much ignorance as you feel necessary (it's a shame, actually, that there isn't a sequence here on lesswrong for maths). What do you advise (if you think the query ill-defined, I would like to know that as well)?