the maths you need to know is pretty simple, but you need to know it. Best way to get it sorted used to be getting in irc and asking spoon or someone, not sure who is in there now. If you can count outs, and are pretty good at multiplying things by 2 and by 4, plus ok at calculating 10% of something and then multiplying that by numbers between 1 and 10 then your maths level is ok, then you just need to work on applying that math.

what should you study? obviously it depends.

you could start with thinking in detail on why each hand is in your utg range, and why icandy would suggest min-opening some of that range.
some stuff is written on that
http://www.flopturnriver.com/pokerfo...ed-174229.html

if you have read and understood these http://www.flopturnriver.com/pokerfo...ds-186705.html then you can win $$ at poker, and isf's strat articles are still some of the best poker resources available