About your last question, do you mean when season 6 and 7 come out on dvd? half of season 6 (It's called volume 5, so I think you already have it.) have already aired and came out on dvd in the us. I think the season will come out worldwide as a whole after the second half of season 6 airs this summer. (I don't know what county you come from).
Season 7 was JUST ordered, (read this handy press release here:http://www.comedycentral.com/press/press_releases/2011/032811_futurama-renewed-for-26-new-episodes.jhtml). it will be like season 6, as in it will be a big 26 episode season split up in two and airing in 2012 and 2013. The dvd for that won't be out for a couple years I guess.
There is a lot of confusion with season numbering, because Production seasons and broadcast seasons were different in the original run, then the movies came out and got counted as a season, then season 6 and 7 are big seasons split up into 2 broadcast seasons. In short, It's a big mess, and I don't have time to explain it.
sorry, I don't have time to answer all your other question. Anyway, welcome to PEEL young one! I've been here for about a year, so I'm still a little newish too.